Here - Laboratoire Kastler Brossel

Abstracts
Organised by Laurent Hilico, LKB, Université d’Evry-Val-d’Essonne, France
and Martina Knoop, PIIM, Université de Provence, France
Secretary : Frédérique Augougnon, Université d’Evry-Val-d’Essonne, France

This workshop has been endorsed by
We acknowledge financial support by

Sponsors

Scientific committee
Michael Drewsen
Pierre Dubé
Olivier Dulieu
Giovanna Morigi
Roee Ozeri
Stephan Schiller
Utako Tanaka
Aarhus University, Denmark
NRC, Canada
CNRS, Orsay, France
UAB, Barcelona, Spain
Weizmann Institute, Israel
Düsseldorf University, Germany
Osaka University, Japan
Organisers
Laurent Hilico
Laboratoire Kastler-Brossel, Université d’Evry
France
Martina Knoop
Physique des Interactions Ioniques et Moléculaires
CNRS - Université de Provence, France

Camping Els Prat

INDEX BY NAME
AUTHOR AUTHORS TITLE
Number
Session
Page
AKERMAN Nitzan N. Akerman, S. Kotler and R. Ozeri Quantum information with Strontium ions at the Weizmann 2-01 I 37
Institute
ALBERT Magnus M. Albert, J.P.Marler, P.F.Herskind, A. Dantan, Cavity QED and Cavity Mediated Cooling Using Ion Coulomb 2-02 I 38
M.B.Langkilde-Lauesen and M.Drewsen
Crystals
BERMUDEZ Alejandro A. Bermudez The Dirac Equation in Trapped ions 2-03 I 39
BRÜSER Delia D. Brüser, T. Collath, D. Eiteneuer, M. Johanning, P.
Kaufmann, P. Kunert, H. Wunderlich and C. Wunderlich
Microstructured ion traps with magnetic gradients greater
than 100 T/m
1-01 I 19
DE CHIARA Gabriele G. De Chiara, S. Fishman, T. Calarco and G. Morigi One-dimensional Coulomb chains at low temperatures 1-02 I 20
DUBE Pierre P. Dubé, A. A. Madej, and J. E. Bernard The 88Sr+ Optical Frequency Standard at the National 3-01 I 53
Research Council
EBLE Johannes W. Schnitzler, N. M. Linke, J. Eble, F. Schmidt-Kaler, and Experimental demonstration of a deterministic single ion 1-11 II 29
K. Singer
source with an expected implantation resolution of a few nm
ERLEKAM Undine C. F. Correia, U. Erlekam, P. Maître and G. Ohanessian Structural characterization of the protonated, phosphorylated 4-01 I 65
dipeptide [Gly-pTyrH]+ in the gas phase
GLORIEUX Quentin Q. Glorieux, R. Dubessy, B. Dubost, S. Removille, T. Generation of relative-intensity squeezed light using four-wave 2-04 I 40
Coudreau, S. Guibal, L. Guidoni, J.P. Likformann, and N. mixing in an rubidium atomic vapor
Sangouard, P. Milman
GONCALVES DE BARROS Helena H. G. Barros, F. Dubin, C. Russo, A. Stute, P. O. From a single-photon emitter to a single ion laser 2-05 I 41
Schmidt, and R. Blatt
HASEGAWA Shuichi S. Hasegawa Isotope selective trapping with linear Paul traps 4-06 II 70
HAUKE Philipp P. Hauke, R. Schmied, T. Roscilde, V. Murg, D. Porras, Quantum phases for the frustrated nearest-neighbor XY model 2-06 I 42
and J. I. Cirac
on the anisotropic triangular lattice
HEMMERLING Börge B. Hemmerling, L. An der Lan, P. O. Schmidt Towards Direct Frequency Comb Spectroscopy Using 3-02 I 54
Quantum Logic
HILICO Laurent JP. Karr, V. I. Korobov, J. Pedregosa, F. Bielsa, A. H2+ vibrational spectroscopy : theoretical results and 3-03 I 55
Douillet and L. Hilico
experimental developments
HUBER Gerhard G. Huber, W. Schnitzler, R. Reichle, K. Singer and F. Ion transport in a segmented Paul trap 1-03 I 21
Schmidt-Kaler
JILEK Mojmir M. Jilek, M. Hejduk, P. Dohnal, I. Korolov, R. Plašil, Cryogenic Electron-Ion Trap 1-04 I 22
J.Glosík, T. Kotrik
KELLER Matthias P. Blythe, A. Mortensen, N. Seymour-Smith, M. Keller Trapped Ion Cavity-QED: Interfacing Ions and Photons 2-07 II 43
and W. Lange
KHROMOVA Anastasiya A. Khromova, A. Varon, B. Scharfenberger, Ch. Piltz, Ch. A linear Paul Trap for ion spin molecules 1-05 I 23
Wunderlich
KIRCHMAIR Gerhard G. Kirchmair, J. Benhelm, F. Zähringer, R. Gerritsma, C. High fidelity quantum gates with trapped 43 Ca + ions 1-06 I 24
F. Roos, and R. Blatt
KOTLER Shlomi N. Akerman, S. Kotler and R. Ozeri Quantum information with Strontium ions at the Weizmann
Institute
2-01 I 37
KUNERT Peter D. Brüser, T. Collath, D. Eiteneuer, M. Johanning, P.
Kaufmann, P. Kunert, H. Wunderlich and C. Wunderlich
Microstructured ion traps with magnetic gradients greater
than 100 T/m
1-01 I 19
LORENZ Ulrich U. J. Lorenz, A. Svendsen, O. V. Boyarkin and T. R. A tandem mass spectrometer for photodissociation
4-02 I 66
Rizzo
spectroscopy of cold biomolecular ions in the gas phase
MANE JUNIOR Ernesto E. Mané, J. Billowes, K. Blaum, P. Campbell, B. Cheal, D. Collinear laser spectroscopy with cooled and trapped 4-03 I 67
Forest, K. Flanagan, G. Neyens, R. Neugart, G. Tungate, radioisotopes at ISOLDE
P. Vingerhoets, D. Yordanov and The ISOLDE
Collaboration
MARCIANTE Mathieu M. Marciante, A. Calisti, C. Champenois, M. Knoop, F. Study of ion dynamics in a radiofrequency trap by molecular 1-07 I 25
Vedel
dynamics simulations
MATJESCHK Robert R. Matjeschk A planar Paul trap 1-08 I 26
MC LOUGHLIN James J. J. McLoughlin, A. H. Nizamani, J. D. Siverns, R. C. Towards ion trap array architectures with 171Yb+ ions 2-12 II 49
Sterling, M. Bevan-Stevenson, N. Davies, J. Grove-Smith,
M. Hughes, B. Johnson, K. Lee, B. S. Pruess, R.
Ramasawmy, D. N. Scrivener, T. Short, and W. K.
Hensinger
MEHLSTAEUBLER Tanja B. Stein, T.E. Mehlstäubler, I. Sherstov, M. Okhapkin, B.
171
Yb + single-ion optical frequency standard 3-05 I 57
Lipphardt, Chr. Tamm, E. Peik
MIHALCEA Bogdan M. B. Mihalcea, O. S. Stoican, Gina T. Visan, L. M. Dinca Multipolar trap geometries for particle trapping under standard 1-09 II 27
and I. N. Mihailescu
reference temperature and pressure conditions
MORTENSEN Anders P. Blythe, A. Mortensen, N. Seymour-Smith, M. Keller Trapped Ion Cavity-QED: Interfacing Ions and Photons 2-07 II 43
and W. Lange
NIEDERMAYR Michaël M. Niedermayr Towards Cryogenic Surface Ion Traps 1-10 II 28
ODOM Brian B. Odom Search for Time-Variation of the Electron-Proton Mass Ratio 3-10 II 62
with MilliKelvin Trapped Molecular Ions
OFFENBERG David D. Offenberg, C. Zhang, B. Roth, and S. Schiller Towards sympathetic cooling of charged proteins 4-04 II 68
PEDREGOSA GUTIERREZ Jofre J. Pedregosa Gutierrez, F. Bielsa, J-P. Karr, A. Douillet
and L. Hilico
Two photon ro-vibrational spectroscopy of H 2 + : From
Hyperbolic to Linear RF trap
3-04 II 56

REMOVILLE Sébastien S. Removille, R. Dubessy, Q. Glorieux, T. Coudreau, S.
Guibal, L. Guidoni, J.P. Likforman, and N. Sangouard
Towards a Quantum memory in trapped ions 2-08 II 44
SCHILLER Stephan S. Vasilyev, S. Schiller, A. Nevsky, A. Grisard, D. Faye, E. Broadly tunable sub-mW CW Narrowband mid-IR Laser
Lallier, Z. Zhang, A. J. Boyland, J. K. Sahu, M. Ibsen, W. Source for Molecular Spectroscopy
A. Clarkson
SCHNEIDER Christian C. Schneider, R. Matjeschk, and T. Schaetz Towards two-dimensionnal quantum simulations with trapped
ions
SCHNITZLER Wolfgang W. Schnitzler, N. M. Linke, J. Eble, F. Schmidt-Kaler, and
K. Singer
Experimental demonstration of a deterministic single ion
source with an expected implantation resolution of a few nm
3-06 II 58
2-09 II 45
1-11 II 29
SCHULZ Stephan St. Schulz, U. Poschinger, F. Ziesel, G. Huber, F. Schmidt Sideband cooling and coherent dynamics in a microchip multisegmented
1-14 II 32
Kaler
ion trap
SEGAL Daniel D. Crick, S. Donnellan, H. Ohadi, I. Bhatti, R.C. Controlling the Motion of Small Numbers of Ions in a Penning 1-15 II 33
Thompson and D.M. Segal,
Trap
SHU Gang G. Shu, N.Kurz, M.Dietrich, A.Kleczewski, G.Howell, Trapped Barium Ions for Quantum Computation, Atomic Clock 2-10 II 46
R.Bowler, J.Salacka, P.Green, B.B.Blinov
and Precise Measurement
STEIN Björn B. Stein, T.E. Mehlstäubler, I. Sherstov, M. Okhapkin, B.
171
Yb + single-ion optical frequency standard 3-05 I 57
Lipphardt, Chr. Tamm, E. Peik
STOICAN Ovidiu O. Stoican, B. Mihalcea, L. Dinca, G. Visan Acoustic excitation of the charged microparticles motion in a 1-12 II 30
linear electrodynamic trap
SVENDSEN Annette U. J. Lorenz, A. Svendsen, O. V. Boyarkin and T. R. A tandem mass spectrometer for photodissociation
4-02 I 66
Rizzo
spectroscopy of cold biomolecular ions in the gas phase
TANAKA Utako U. Tanaka, R. Naka, F. Iwata, T. Ujimaru, K. R. Brown, I. Design and Characterization of a Planar Trap 1-13 II 31
L. Chuang and S. Urabe
THOMPSON Richard R.C. Thompson, D.M. Segal, S. Bharadia, W.
An Ion Trap for laser spectroscopy of cold highly-charged ions 4-07 II 71
Nörtershäuser, D.F.A. Winters, M. Vogel, Z. Andjelkovic
and the SPECTRAP collaboration
VON ZANTHIER Joachim J. von Zanthier, Ch. Thiel, Th. Bastin, G. S. Agarwal Quantum imaging with trapped ions 2-11 II 47
WAGNER Anke A. Wagner, K. Blaum, W. Quint, B. Schabinger, S. Sturm Design of a battery-based low noise voltage source 3-07 I 59
WERTH Guenter S. Kreim, J. Alonso, K. Blaum, H.-J. Kluge, W. Quint, B. Test of QED and CPT via g-factors 3-08 II 60
Schabinger, S. Stahl, S. Ulmer, J. Verdu, M. Vogel, J.
Walz, G. Werth
WILLITSCH Stephan S. Willitsch, M. T. Bell, A. D. Gingell, J. M. Oldham and T. Cold Chemistry with Cold Ions 4-05 II 69
P. Softley
ZUMSTEG Cédric C. Zumsteg, C. Champenois, G. Hagel, M. Houssin, D.
Guyomarc’h, F. Vedel, M. Knoop
A single Ca + ion for optical frequency metrology 3-09 II 61

INDEX BY NUMBER
AUTHOR AUTHORS TITLE
BRÜSER Delia D. Brüser, T. Collath, D. Eiteneuer, M. Johanning, P.
Kaufmann, P. Kunert, H. Wunderlich and C. Wunderlich
KUNERT Peter D. Brüser, T. Collath, D. Eiteneuer, M. Johanning, P.
Kaufmann, P. Kunert, H. Wunderlich and C. Wunderlich
Microstructured ion traps with magnetic gradients greater
than 100 T/m
Microstructured ion traps with magnetic gradients greater
than 100 T/m
Number
Session
Page
1-01 I 19
1-01 I 19
DE CHIARA Gabriele G. De Chiara, S. Fishman, T. Calarco and G. Morigi One-dimensional Coulomb chains at low temperatures 1-02 I 20
HUBER Gerhard G. Huber, W. Schnitzler, R. Reichle, K. Singer and F. Ion transport in a segmented Paul trap 1-03 I 21
Schmidt-Kaler
JILEK Mojmir M. Jilek, M. Hejduk, P. Dohnal, I. Korolov, R. Plašil, Cryogenic Electron-Ion Trap 1-04 I 22
J.Glosík, T. Kotrik
KHROMOVA Anastasiya A. Khromova, A. Varon, B. Scharfenberger, Ch. Piltz, Ch. A linear Paul Trap for ion spin molecules 1-05 I 23
Wunderlich
KIRCHMAIR Gerhard G. Kirchmair, J. Benhelm, F. Zähringer, R. Gerritsma, C. High fidelity quantum gates with trapped 43 Ca + ions 1-06 I 24
F. Roos, and R. Blatt
MARCIANTE Mathieu M. Marciante, A. Calisti, C. Champenois, M. Knoop, F. Study of ion dynamics in a radiofrequency trap by molecular 1-07 I 25
Vedel
dynamics simulations
MATJESCHK Robert R. Matjeschk A planar Paul trap 1-08 I 26
MIHALCEA Bogdan M. B. Mihalcea, O. S. Stoican, Gina T. Visan, L. M. Dinca Multipolar trap geometries for particle trapping under standard 1-09 II 27
and I. N. Mihailescu
reference temperature and pressure conditions
NIEDERMAYR Michaël M. Niedermayr Towards Cryogenic Surface Ion Traps 1-10 II 28
EBLE Johannes W. Schnitzler, N. M. Linke, J. Eble, F. Schmidt-Kaler, and Experimental demonstration of a deterministic single ion 1-11 II 29
K. Singer
source with an expected implantation resolution of a few nm
SCHNITZLER Wolfgang W. Schnitzler, N. M. Linke, J. Eble, F. Schmidt-Kaler, and Experimental demonstration of a deterministic single ion 1-11 II 29
K. Singer
source with an expected implantation resolution of a few nm
STOICAN Ovidiu O. Stoican, B. Mihalcea, L. Dinca, G. Visan Acoustic excitation of the charged microparticles motion in a 1-12 II 30
linear electrodynamic trap
TANAKA Utako U. Tanaka, R. Naka, F. Iwata, T. Ujimaru, K. R. Brown, I. Design and Characterization of a Planar Trap 1-13 II 31
L. Chuang and S. Urabe
SCHULZ Stephan St. Schulz, U. Poschinger, F. Ziesel, G. Huber, F. Schmidt Sideband cooling and coherent dynamics in a microchip multisegmented
1-14 II 32
Kaler
ion trap
SEGAL Daniel D. Crick, S. Donnellan, H. Ohadi, I. Bhatti, R.C. Controlling the Motion of Small Numbers of Ions in a Penning 1-15 II 33
Thompson and D.M. Segal,
Trap
AKERMAN Nitzan N. Akerman, S. Kotler and R. Ozeri Quantum information with Strontium ions at the Weizmann 2-01 I 37
Institute
KOTLER Shlomi N. Akerman, S. Kotler and R. Ozeri Quantum information with Strontium ions at the Weizmann 2-01 I 37
Institute
ALBERT Magnus M. Albert, J.P.Marler, P.F.Herskind, A. Dantan, Cavity QED and Cavity Mediated Cooling Using Ion Coulomb 2-02 I 38
M.B.Langkilde-Lauesen and M.Drewsen
Crystals
BERMUDEZ Alejandro A. Bermudez The Dirac Equation in Trapped ions 2-03 I 39
GLORIEUX Quentin Q. Glorieux, R. Dubessy, B. Dubost, S. Removille, T. Generation of relative-intensity squeezed light using four-wave 2-04 I 40
Coudreau, S. Guibal, L. Guidoni, J.P. Likformann, and N. mixing in an rubidium atomic vapor
Sangouard, P. Milman
GONCALVES DE BARROS Helena H. G. Barros, F. Dubin, C. Russo, A. Stute, P. O. From a single-photon emitter to a single ion laser 2-05 I 41
Schmidt, and R. Blatt
HAUKE Philipp P. Hauke, R. Schmied, T. Roscilde, V. Murg, D. Porras, Quantum phases for the frustrated nearest-neighbor XY model 2-06 I 42
and J. I. Cirac
on the anisotropic triangular lattice
KELLER Matthias P. Blythe, A. Mortensen, N. Seymour-Smith, M. Keller Trapped Ion Cavity-QED: Interfacing Ions and Photons 2-07 II 43
and W. Lange
MORTENSEN Anders P. Blythe, A. Mortensen, N. Seymour-Smith, M. Keller Trapped Ion Cavity-QED: Interfacing Ions and Photons 2-07 II 43
and W. Lange
REMOVILLE Sébastien S. Removille, R. Dubessy, Q. Glorieux, T. Coudreau, S.
Guibal, L. Guidoni, J.P. Likforman, and N. Sangouard
Towards a Quantum memory in trapped ions 2-08 II 44
SCHNEIDER Christian C. Schneider, R. Matjeschk, and T. Schaetz Towards two-dimensionnal quantum simulations with trapped 2-09 II 45
ions
SHU Gang G. Shu, N.Kurz, M.Dietrich, A.Kleczewski, G.Howell, Trapped Barium Ions for Quantum Computation, Atomic Clock 2-10 II 46
R.Bowler, J.Salacka, P.Green, B.B.Blinov
and Precise Measurement
VON ZANTHIER Joachim J. von Zanthier, Ch. Thiel, Th. Bastin, G. S. Agarwal Quantum imaging with trapped ions 2-11 II 47
MC LOUGHLIN James J. J. McLoughlin, A. H. Nizamani, J. D. Siverns, R. C. Towards ion trap array architectures with 171Yb+ ions 2-12 II 49
Sterling, M. Bevan-Stevenson, N. Davies, J. Grove-Smith,
M. Hughes, B. Johnson, K. Lee, B. S. Pruess, R.
Ramasawmy, D. N. Scrivener, T. Short, and W. K.
Hensinger
DUBE Pierre P. Dubé, A. A. Madej, and J. E. Bernard The 88Sr+ Optical Frequency Standard at the National 3-01 I 53
Research Council
HEMMERLING Börge B. Hemmerling, L. An der Lan, P. O. Schmidt Towards Direct Frequency Comb Spectroscopy Using
Quantum Logic
3-02 I 54

HILICO Laurent JP. Karr, V. I. Korobov, J. Pedregosa, F. Bielsa, A. H2+ vibrational spectroscopy : theoretical results and 3-03 I 55
Douillet and L. Hilico
experimental developments
PEDREGOSA GUTIERREZ Jofre J. Pedregosa Gutierrez, F. Bielsa, J-P. Karr, A. Douillet Two photon ro-vibrational spectroscopy of H + 2 : From 3-04 II 56
and L. Hilico
Hyperbolic to Linear RF trap
MEHLSTAEUBLER Tanja B. Stein, T.E. Mehlstäubler, I. Sherstov, M. Okhapkin, B.
171
Yb + single-ion optical frequency standard 3-05 I 57
Lipphardt, Chr. Tamm, E. Peik
STEIN Björn B. Stein, T.E. Mehlstäubler, I. Sherstov, M. Okhapkin, B.
171
Yb + single-ion optical frequency standard 3-05 I 57
Lipphardt, Chr. Tamm, E. Peik
SCHILLER Stephan S. Vasilyev, S. Schiller, A. Nevsky, A. Grisard, D. Faye, E. Broadly tunable sub-mW CW Narrowband mid-IR Laser 3-06 II 58
Lallier, Z. Zhang, A. J. Boyland, J. K. Sahu, M. Ibsen, W. Source for Molecular Spectroscopy
A. Clarkson
WAGNER Anke A. Wagner, K. Blaum, W. Quint, B. Schabinger, S. Sturm Design of a battery-based low noise voltage source 3-07 I 59
WERTH Guenter S. Kreim, J. Alonso, K. Blaum, H.-J. Kluge, W. Quint, B. Test of QED and CPT via g-factors 3-08 II 60
Schabinger, S. Stahl, S. Ulmer, J. Verdu, M. Vogel, J.
Walz, G. Werth
ZUMSTEG Cédric C. Zumsteg, C. Champenois, G. Hagel, M. Houssin, D. A single Ca + ion for optical frequency metrology 3-09 II 61
Guyomarc’h, F. Vedel, M. Knoop
ODOM Brian B. Odom Search for Time-Variation of the Electron-Proton Mass Ratio 3-10 II 62
with MilliKelvin Trapped Molecular Ions
ERLEKAM Undine C. F. Correia, U. Erlekam, P. Maître and G. Ohanessian Structural characterization of the protonated, phosphorylated 4-01 I 65
dipeptide [Gly-pTyrH]+ in the gas phase
LORENZ Ulrich U. J. Lorenz, A. Svendsen, O. V. Boyarkin and T. R. A tandem mass spectrometer for photodissociation
4-02 I 66
Rizzo
spectroscopy of cold biomolecular ions in the gas phase
SVENDSEN Annette U. J. Lorenz, A. Svendsen, O. V. Boyarkin and T. R. A tandem mass spectrometer for photodissociation
4-02 I 66
Rizzo
spectroscopy of cold biomolecular ions in the gas phase
MANE JUNIOR Ernesto E. Mané, J. Billowes, K. Blaum, P. Campbell, B. Cheal, D. Collinear laser spectroscopy with cooled and trapped 4-03 I 67
Forest, K. Flanagan, G. Neyens, R. Neugart, G. Tungate, radioisotopes at ISOLDE
P. Vingerhoets, D. Yordanov and The ISOLDE
Collaboration
OFFENBERG David D. Offenberg, C. Zhang, B. Roth, and S. Schiller Towards sympathetic cooling of charged proteins 4-04 II 68
WILLITSCH Stephan S. Willitsch, M. T. Bell, A. D. Gingell, J. M. Oldham and T. Cold Chemistry with Cold Ions 4-05 II 69
P. Softley
HASEGAWA Shuichi S. Hasegawa Isotope selective trapping with linear Paul traps 4-06 II 70
THOMPSON Richard R.C. Thompson, D.M. Segal, S. Bharadia, W.
Nörtershäuser, D.F.A. Winters, M. Vogel, Z. Andjelkovic
and the SPECTRAP collaboration
An Ion Trap for laser spectroscopy of cold highly-charged ions 4-07 II 71

NOVEL ION TRAP DESIGN

Microstructured ion traps with magnetic gradients greater than 100 T/m
Delia Brüser 1 , Thomas Collath 1 , Daniel Eiteneuer 1 , Michael Johanning 1 , Peter Kaufmann 1 , Peter
Kunert 1 , Harald Wunderlich 1 and Christof Wunderlich 1
1
Working Group Quantenoptik, University of Siegen, Walter Flex Str. 3, 57072 Siegen
Strings of laser cooled ions stored in microstructured Paul traps (Microtraps) have promising
potential for quantum optics. They provide a system which can be screened from decohering
environment, accurately prepared in a large variety of states and manipulated with high accuracy.
Furthermore, state detection can be achieved with almost unit efficiency.
We will expose Ytterbium ions to a magnetic field gradient. This allows us to address the ions in
the frequency space [1], [2]. Furthermore, long distance spin-spin coupling of the ions’ internal
states is induced by the gradient, which is proportional in strength to the square of the magnetic
gradient [1]. The spin-spin coupling is useful for building a quantum computer, for quantum
simulations and for studying quantum phase transitions.
Microstructured current flow has proven successful in the
creation of magnetic fields [3]. In those cases, large gradients are
found only very close to the substrate surface. For our trap, the
challenge is to create large gradients over extended ion strings as
far away as possible from the surface to avoid heating which
scales steeply with the ion surface separation.
Our microtrap consists of a three layer structure (based on a
design by F. Schmidt-Kaler et al., University of Ulm, see figure on
the right). The outer layers apply DC and AC electric fields for
3D trapping whilst the middle layer is used to form an
inhomogeneous magnetic field. This is realized by having the electric current flow around the
inner edge of the middle layer which works as a section of a circular coil (see figure below). We
form an Anti Helmholtz coil by two of these geometries with opposite current flow.
We want to achieve as large coupling constants as
possible. Therefore, we need large gradients. A large
magnetic gradient results in both large frequency
separation and coupling constants. We developed a
middle layer design which was optimized with respect to
gradient per dissipated heat. From simulations and first
tests with prototypes we expect this design to allow gradients greater than 100 T/m.
[1] F. Mintert, C. Wunderlich, Phys. Rev. Lett. 87, 257904 (2001); C. Wunderlich, in Laser
Physics at the Limit (Springer, Heidelberg, 2002), p. 261, arXiv:0111158v1 [quant-ph]; C.
Wunderlich, C. Balzer, Adv. At., Mol., Opt. Phys. 49, 293, (2003).
[2] M. Johanning, A. Braun, N. Timoney, V. Elman, W. Neuhauser, C. Wunderlich,
arXiv:0801.0078v1 [quant-ph].
[3] S. Groth, P. Krüger, S. Wildermuth, R. Folman, T. Fernholz, J. Schmiedmayer, Appl. Phys.
Lett. 85, 2980(2004).

One-dimensional Coulomb chains at low temperatures
G. De Chiara 1 , S. Fishman 2 , T. Calarco 3 and G. Morigi 1
1 Universitat Autonoma de Barcelona, Bellaterra, Spain
2 Department of Physics, Technion, Haifa, Israel
3 Institute for Quantum Information Processing, University of Ulm, Ulm, Germany
Coulomb crystals are organized structures of charged particles, which interact through
the Coulomb repulsion and arrange in regular patterns at sufficiently low temperatures
in the presence of a confining potential [1]. These potentials are realized by means of
Paul or of Penning traps, and their geometry determines the crystal structure. These
crystals represent a kind of rarefied condensed matter, the inter-particle distance being
of the order of several micrometers, allowing to studying the structure by means of
optical radiation. The crystal shape as well as the number of ions can be controlled by
varying the potential. Several remarkable experiments have reported crystallization of
ion gases in Paul and Penning traps [1].
Here, we report on recent works, in which we studied the dynamics, thermodynamics
and mechanical instability of Coulomb chains. Coulomb chains are one-dimensional
structures, obtained by means of strong transverse confinement and that usually consist
of dozens of ions localized along the trap axis. They represent a peculiar crystallized
structure: due to the axial potential the equilibrium charge distribution is not uniform.
This is in contrast to the three-dimensional case, where the density of charges in a
harmonic potential is uniform and, therefore, where the eigenmodes are phononic-like
waves. In the Coulomb chain the non-uniformity of the density of ions combined with
the long-range interaction result in excitations that are fundamentally different from the
phonons in solids and lead to interesting thermodynamic properties. Using these results
we discuss the statistical mechanics of the chain, and derive some thermodynamic
quantities such as the specific heat for which we find a non-extensive behaviour [2].
These results allow us to evaluate the critical aspect ratio between the frequencies of the
transverse and the axial confining potential, which determines the stability of the linear
chain. At this value of the aspect ratio, in fact, the crystal structure undergoes an abrupt
transition from a chain to a zigzag configuration. We study the structural phase
transition in the thermodynamic limit, by developing an analytic theory which describes
the behaviour of the system at the critical point [3]. From symmetry considerations we
conjecture the spontaneous symmetry breaking. Applying Landau theory, we identify
the order parameter with the displacement of the equilibrium position from the trap axis,
while the control parameter can be taken as the transverse frequency when the interparticle
distance is fixed. The soft mode, whose frequency becomes zero at the critical
point, is the transverse mode at the shortest wavelength, the so called zigzag mode. Our
theory is valid at T=0, when the system exhibits long-range order. The results we find
are in agreement with the numerical results reported in [4].
________________
[1] D. H. Dubin and T. M. O’Neil, Rev. Mod. Phys. 71, 87 (1999).
[2] G. Morigi and Sh. Fishman, Phys. Rev. Lett 93, 170602 (2004); Phys. Rev. E 70,
066141 (2004).
[3] Sh. Fishman, G. De Chiara, T. Calarco, G. Morigi, Phys. Rev. B 77, 064111 (2008).
[4] J. P. Schiffer, Phys. Rev. Lett. 70, 818 (1993). G. Piacente, I. V. Schweigert, J. J.
Betouras, and F. M. Peeters, Phys. Rev. B 69, 045324 (2004).

Ion transport in a segmented Paul trap
G. Huber, W. Schnitzler, R. Reichle, K. Singer and F. Schmidt-Kaler
Institute for Quantum Information Processing, University of Ulm,
Albert-Einstein-Allee 11, 89069 Ulm, Germany
Segmented linear Paul traps are one of the most promising candidates for the
implementation of scalable quantum computing [1]. One key requirement for scalability
is the ability to split strings of ions and transport ions carrying quantum
information between different regions in a trap, e.g. a storing and a processing unit.
We present a segmented linear Paul trap meeting these requirements. It provides
15 pairs of electrodes generating almost arbitrary potentials along the trap axis
including time dependent transport wells, non-harmonic splitting potentials and
multiple trap configurations.
Single 40 Ca + -ions and strings of ions generated by isotope selective photoionization
are confined in the radio frequency Paul trap, laser cooled and detected by their
fluorescence on a CCD camera. Both radial and axial trap frequencies have been
measured and agree with predicted values from numerical calculations with the
precision of a few percent – a necessity for tailoring manipulation potentials. By
applying time dependent voltages [2] to the 15 segment pairs we are able to control
the ion positions over macroscopic distances in a deterministic way, thus splitting and
merging ion chains and transporting single ions over a distance of several millimeters
without loss with a success probability over 99.8%.
References
[1] D. Kielpinsky et al. Nature 417, 709 (2002).
[2] G. Huber et al. New J. Phys. 10, 013004 (2008).
1

Cryogenic Electron-Ion Trap
M. Jilek, T. Kotrík, M. Hejduk, P. Dohnal, I. Korolov, R. Plašil, J.Glosík (*)
Faculty of Mathematics and Physics, Charles University in Prague, Czech Republic
(*) juraj.glosik@mff.cuni.cz
For study of electron-ion recombination and electron attachment at cryogenic collision
energies (down to 10 K) we are constructing electron-ion trap.
The electron trap will use electrostatic field and magnetic field from permanent magnets
for confinement of electrons (using strong gradient of magnetic field - magnetic mirror
like). FEMM (Finite Element Method Magnetic) program is used to model magnetic field
in the trap. The trap is axially symmetric. The calculations were confirmed by
measurement of the magnetic field in the prototype of the trap.
Trapped electrons will be cooled by collisions with Helium buffer gas. The density of
electrons will be roughly 10 7 cm -3 , i.e. high enough to form 3-dimensional potential
minimum on the axis of the trap. The ions formed in external ion source will be trapped
in three dimensional potential minimum created by electrodes and trapped electrons (sort
of nested trap). The trapped plasma will be cooled by elastic collisions with cold helium
(or hydrogen) buffer gas. PIC calculations of electron injection, trapping, confinement
and cooling are carried out and the results will be presented. The electron and ion
trapping and cooling were simulated using code XOOPIC code. Calculated configuration
of magnetic field is used in the XOOPIC calculations.
In the calculation 2×10 7 electrons and 1×10 5 ions are injected into the trap and time
evolution of the plasma cloud is calculated. Helium buffer fills center of the trap.
Presented will be the design and construction of the trap.
In the experiment the decay of the ion density due to recombination with electrons will be
monitored and recombination rate coefficient will be obtained. Low temperature and
relatively high density of electrons can open possibility for study of Collisional radiative
recombination, which has rate proportional to T -4.5 , so it can be at 10 K very fast and
competitive to dissociative recombination.
Acknowledgements: This work is a part of the research plan MSM 0021620834 financed by the
Ministry of Education of the Czech Republic and was partly supported by GACR (202/08/H057,
202/07/0495) by GAUK 53607 and GAUK 124707.

A LINEAR PAUL TRAP FOR ION SPIN MOLECULES
A. Khromova 1 , A. Varon 1 , B. Scharfenberger 1 , Ch. Piltz 1 , Ch. Wunderlich 1
1 Fachbereich Physik, University of Siegen, Walter-Flex Str.3, 57072 Siegen, Germany
Individual atomic ions confined in an electrodynamic cage are a promising system for various
tasks in quantum information science and related fields [1]. In particular, a system of pair-wise
coupled individually accessible spins is useful for experimentally investigating a wide range of topics
in physics. We work on the implementation of a pseudo-spin many-body system, an “ion spin
molecule”, that is, a string of laser cooled atomic ions confined in an electrodynamic trap that is
modified such that an adjustable spin-spin coupling between ions is induced [2]. This will allow for
the well controlled generation and analysis of a large entangled spin system. Examples where this will
be useful include: testing new methods for determining efficiently the entanglement of a many body
system, investigating the decoherence properties of such systems, exploring quantum simulations, or
implementing a neural network.
The current state of our experimental setup will be reported: new linear ion trap, vacuum
chamber organization, laser systems and wavelength meter. The new linear ion tarp was built. SmCo
permanent magnets were added to the design. With the help of them a magnetic field gradient of
20T/m is expected. The ions used in our experiment are 171 Yb + and 172 Yb + . For 171 Yb + experiment
microwave antenna was proposed which will deliver higher magnetic fields into the trap centre. It
makes it possible to control as well which transition of the hyperfine levels we would like to excite.
Light at 369nm and 935nm is used to perform the cooling cycle together with the microwave
source for 171 Yb + . Another two wavelength used in our experiment are 399nm for photoionization and
638nm for repumping the metastable state F 7/2 . All four wavelengths are produced by diode laser
systems frequency stabilized using side-of-fringe frequency stabilization. The general frequency
control scheme will be demonstrated.
For precise measurements of the lasers’ wavelengths the wavelength meter was designed. It is
based on the Michelson interferometer. As a reference frequency, used for locking, the cross-over
signal (linewidth ~6MHz) of the 5 2 P 3/2 , F=3 ↔ 5 2 S 1/2 , F=2 transition in the Rubidium atom is used.
Light at 780,027nm (D2 transition) is produced by a diode laser. The details of the construction will be
highlighted.
[1] J.I. Cirac and P. Zoller, Phys. Rev. Lett. 74, 4091 (1995); D. Leibfried et al., Nature 438, 639
(2005); H.Häffner et al., Nature 438, 643 (2005)
[2] Ch.Wunderlich, Conditional Spin Resonance with Trapped Ions, Laser Physics at the Limits,
p.261, (Springer, 2002); Ch.Wunderlich and Ch.Balzer, Adv. At. Mol. Opt. Phys. 49, 295 (2003)

High fidelity quantum gates with trapped 43 Ca + ions.
G. Kirchmair 1,2 , J. Benhelm 1,2 , F. Zähringer 1,2 , R. Gerritsma 1,2 , C. F. Roos 1,2 , and R. Blatt 1,2
1 Institut für Experimentalphysik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
2 Institut für Quantenoptik und Quanteninformation,
ÖAW, Otto-Hittmair-Platz 1, A-6020 Innsbruck, Austria
For fault-tolerant computation, it is commonly believed that error thresholds ranging
between 10 −4 and 10 −4 will be required depending on the noise model and the computational
overhead for realizing the quantum gates. Up to now, all experimental implementations have
fallen short of these requirements.
I report on a Mølmer-Sørensen type gate operation entangling states with a fidelity of
99.3% which together with single-qubit operations forms an universal set of quantum gates.
The gate operation is performed on a pair of qubits encoded in two trapped calcium ions using
a single amplitude-modulated laser beam interacting with both ions at the same time. A
robust gate operation, mapping separable states onto maximally entangled states, is achieved
by adiabatically switching on and off the laser-ion coupling. We analyse the performance of
a single gate and concatenations of up to 21 gate operations.

Study of ion dynamics in a radiofrequency trap
by molecular dynamics simulations
Mathieu Marciante, Annette Calisti, Caroline Champenois, Martina Knoop, Fernande Vedel
Physique des Interactions Ioniques et Moléculaires (CNRS UMR6633),
Université de Provence, Centre de Saint Jérôme, case C21, Marseille cedex 20, France
Molecular Dynamics simulations are carried out to evaluate the general behaviour of the
dynamics of ions in a radiofrequency trap. We present the different types of motion allowed
by this kind of device for a single ion and compare it with the secular approximation that can
be done, finding thus the limits of this approximation. Single ions can be followed in a small
ion cloud allowing to evidence the mobility in the Coulomb crystal for different pseudopotentiel
well depths (figure).
Figure: Projection of the motion of 40 Ca + ions for two different pseudopotential well depths
(V AC =800V, Ω/2π=10 MHz, above U DC =0V, below U DC =4V), blue points. Green points follow the motion
of a single ion during 2000 rf periods. Left: x-y, centre: x-z, right: symmetry of the potential well depth
We then illustrate some periodic and chaotic trajectories by analyzing the dimensionless
Poincaré section of our system. We present the structures of a thermalized ion cloud for
different values of the confinement parameters and the organization of a two-species ion
cloud. These structures are finally used to simulate the observations carried out by a CCD
camera.
At present simulations are extended to different confinement potentials in a linear
configuration, in particular octupole [1] and dodecapole trap, where the dynamics of a large
ion cloud will be studied experimentally.
[1] K. Okada, K. Yasuda, T. Takayanagi, M. Wada, H.A. Schuessler, S. Ohtani, Crystallization of Ca +
ions in a linear rf octupole ion trap, Phys. Rev. A 75, 033409 (2007)

A planar Paul trap
Robert Matjeschk
An approach to investigate the dynamics of quantum many-body systems
is quantum simulations. A promising realisation is the simulation based on
ions in Paul traps. Besides the principle study of feasibility, an important
issue is scalability - the possibility to confine and control many ions. Quantum
simulations using an order of 10x10 ions - still a challenging dream - are
supposed to lead to new insight into quantum many-body dynamics.
In linear traps this scalability is hindered by the fact that all ions are
trapped in one effective oscillator potential. This leads for example to a
non-homogeneous distance distribution and thus to a non-homogeneous interaction
strength distribution between the ions.
Our group has successfully simulated a quantum magnet consisting of
two interacting spins using ions in a linear Paul trap [1]. Increasing the spinspin
interaction adiabatically from zero to a specific (large) value led to a
transition from a paramagnetic to a ferromagnetic state with a probability of
98 %. We were able to prove, that with a fidelity of 88 % the system evolved
into a superposition state | ↑↑〉+| ↓↓〉, being equivalent to an entangled state.
To be able to address more complex systems, we are developing a 2Dsurface-trap
where four ions will be arranged in a two-dimensional plane.
Each ion will be confined in its own effective oscillator potential, while the
(homogeneous) distance between the ions is still small enough (about 20
µm) to maintain a non-negligible ion-ion interaction (mediated by coulomb
forces). Such a trap design should in principle be scalable.
[1] to be published (see arxiv 0802.4072v2)
1

Multipolar trap geometries for particle trapping under standard
reference temperature and pressure conditions
B. M. Mihalcea, O. S. Stoican, Gina T. Vişan, L. M. Dincă and I. N. Mihăilescu
National Institute for Laser, Plasma and Radiation Physics (INFLPR), Bucharest-Măgurele, Romania
E-mail: bmihal@infim.ro; stoican@infim.ro
Generation of nonlinear states (especially entangled states) in ion traps [1] increases the
signal-to-noise ratio in spectroscopy and will enable future implementation of quantum logic [2]
as well as future progress on the realization of very high accuracy atomic clocks. That is why
current interest is centered on minimizing the perturbing mechanisms associated to the trapping
phenomenon, such as the second order Doppler shift, decoherence mechanisms, etc. We have
designed and tested new linear multipolar trap geometries, operating in air, under standard
temperature and pressure reference conditions [3]. Our main interest was focused on illustrating
the trapping phenomenon for such trap geometries and study microparticle dynamics. After
testing different geometries and geometrical configurations, we have investigated an octupole
trap geometry and a dodecapole trap geometry, presented in Fig. 1 and Fig. 2. The trap
electrodes, equidistantly spaced, are made of brass. An electronic system which we designed is
used in order to generate the trapping voltages, as well as the voltage used for particle diagnosis.
We have generated microplasmas and investigated the ordering conditions for different trapping
parameters, using microparticle species such as SiC and Al 2 O 3 . The two traps are currently
undergoing tests in our group and a numerical simulation on the particle dynamics is approached.
Figure 1: octupole trap geometry
Figure 2: dodecapole trap geometry
References
[1] P. K. Ghosh, Ion Traps, Clarendon Press, Oxford (1995)
[2] I. Zutic, J. Fabian, and S. Das Sarma, Rev. Mod. Phys. 76, 323 (2004)
[3] O. S. Stoican, B. M. Mihalcea, L. C. Giurgiu, and I. N. Mihăilescu, Satellite Meeting Atomic
Physics with Trapped Ions, 23-24 July 2006, Innsbruck, Book of abstracts, P43 (2006)

Michael Niedermayr
Universität Innsbruck – Institut für Experimentalphysik
Towards Cryogenic Surface Ion Traps
One promising approach for scalable quantum information processing (QIP) architectures is
based on miniaturized surface ion traps [1]. These traps with dimensions in the sub-100µm
range can be fabricated by photolithography techniques [2]. Generally, experimental results
indicate that the heating rate of the ions increases with decreasing trap dimensions.
The mechanism of this heating is not yet fully understood. However, the heating rate can be
reduced by several orders of magnitude when the trap electrodes are cooled from room
temperature to 4K [3, 4].
Within a new experiment which is presently set up we intend to investigate surface traps at
low temperatures in a cryogenic system. These traps will be applied for quantum simulations,
for fundamental investigations of large-scale entanglement and for precision measurements
enhanced by quantum metrology techniques employing entangled particles.
[1] D. Kielpinski et al., Nature 417, 709 (2002)
[2] J. Chiaverini et al., Quantum Inf. Comput. 5, 419 (2005)
[3] J. Labaziewicz et al., Phys. Rev. Lett. 100, 013001 (2008)
[4] L. Deslauriers et al., Phys. Rev. Lett. 97, 103007 (2006)

Experimental demonstration of a deterministic single ion source with an
expected implantation resolution of a few nm
W. SCHNITZLER, N. M. LINKE, J. EBLE, F. SCHMIDT-KALER, and K. SINGER –
Universität Ulm, Institut für Quanteninformationsverarbeitung, Albert-Einstein-Allee 11,
89069 Ulm, Germany
We have realized a universal deterministic single ion source on the basis of an ion trap
applicable to a wide range of elements and molecules [1]. Initially, cold 40 Ca + ion crystals are
trapped within a segmented linear trap. Those ions are then deterministically extracted and
shot into a detector at a distance of 25 cm from the trap. With single ions, more than 90% of
these extractions were successful. The kinetic energy distribution of the ions amounts to less
than 0.1%. We have also demonstrated the extraction of mixed ion crystals containing other
dopant ions.
For the implantation with nm precision, we plan to utilize an electrostatic Einzel-lens to
further improve the spatial resolution of the extracted ions. These can then be used to generate
color centers in diamond for optical detection or to implant P into Si. Both systems provide
the foundation for the realization of a solid state quantum computer [2,3]. In addition, the
electrical properties of semiconductor devices can be greatly enhanced by the deterministic
implantation of single ions [4].
[1] J. Meijer et. al., Appl. Phys. A 83, 321 (2006)
[2] F. Jelezko et. al., Phys. Rev. Lett. 93, 130501 (2004)
[3] B. E. Kane, Nature 393, 133 (1998)
[4] T. Shinada et. al., Nature 437, 1128 (2005)

Acoustic excitation of the charged microparticles motion in a linear
electrodynamic trap
O. S. Stoican, B. Mihalcea, L. Dinca, G. Visan
INFLPR, 409Atomistilor St., Magurele, 077125 Romania
stoican@infim.ro
An experimental study on the interaction between an acoustic wave and the charged
microparticles stored in a linear electrodynamic trap is presented. The linear
electrodynamic trap consists of four bar electrodes equidistantly spaced, supplied by a
high ac voltage Vcos2πft, and two endcap disc electrodes. A dc voltage applied to the
endcap electrodes assures the axial stability of the stored particles. The microparticles
consisting of Al 2 O 3 powder, 63-200 μm in diameter, have been stored in air at normal
pressure. The output beam of a low power laser module is focused on the longitudinal
axis of the linear trap where the density of the stored microparticles has a maximum
value. A fraction of the radiation scattered by the stored microparticles is received by an
integrated photodetector, directed normal to the linear trap axis, and converted into an
electrical voltage. The motion of the stored particles modulates the intensity of the
scattered radiation so that photodetector output voltage has the same harmonic
components. One of the dominant harmonics is due to the so-called “micromotion” at
frequency f of the ac supply voltage. The amplitude A(f) of the photodetector output
voltage harmonic component at frequency f is measured using a synchronous detection
technique. Supplementary force field acting on the stored microparticles is produced
using an acoustic wave generated by a loudspeaker. Effects of the acoustic wave are
studied observing the time variation of the amplitude A(f). The beat oscillations due to the
action of the acoustic wave have been evidenced. Because the action of the acoustic wave
is purely mechanical this experimental approach allows decoupling the mass m and the
electric charge q, respectively, from equation of motion of the stored microparticles.
Results are discussed.

Design and Characterization of a Planar Trap
U. Tanaka 1, 2 , R. Naka 1 , F. Iwata 1 , T. Ujimaru 1 , K. R. Brown 3 , I. L. Chuang 4 and S. Urabe 1, 2
1 Graduate School of Engineering Science, Osaka University, Japan, 2 JST-CREST, Japan
3 School of Chemistry and Biochemistry, Division of Computational Science and Engineering,
Georgia Institute of Technology, USA
4 Center for Bits and Atoms and Department of Physics, Massachusetts Institute of Technology, USA
Planar traps [1-4] have substantial potential for realizing large-scale quantum information
processing such as quantum CCD [5] since its structure is suitable for fabrication of complicated
geometries. We report experiments of 40 Ca + ions with a planar trap whose layout of electrodes is
shown in Fig. 1. It is made of a low-rf-loss substrate and deposited with copper. The potential
minimum is estimated to be located about 0.8 mm above the surface of the center electrode and the
typical potential depth is about 1 eV. Calcium ions are loaded by two-step photo-ionization using a
423 nm diode laser for the 4s 2 1 S 0 - 4s4p 1 P 1 transition and a light emitting diode for the second
excitation [6]. Laser cooling and detection of ions are performed with the 4s 2 S 1/2 - 4p 2 P 1/2 transition
at 397 nm and the 4p 2 P 1/2 - 3d 2 D 3/2 transition at 866 nm. Laser beams that are parallel to the trap
surface are irradiated as shown in Fig. 1.
We measured the motional frequencies of ions and compared them to those estimated by
simulation. Brief micromotion compensation was performed in the x-z plane by varying the DC
voltages with monitoring fluorescence spectra. Figure 2 shows an image of two 40 Ca + ions aligned in
the z direction.
We also discuss miniaturization of the trap and other designs and show simulated results.
Laser beam
(397 nm)
End electrode
DC electrodes
End electrode
x
z
Laser beams
(397 nm, 866 nm,
423 nm)
RF electrode
Center electrode
1.5mm
End electrode DC electrodes End electrode
Fig. 1
Layout of trap electrodes.
10m
Fig. 2 Two 40 Ca + ions confined in the planar trap.
[1] J. Chiaverini et al., Quantum Inf.Comput. 5, 419-439 (2005)
[2] C. E. Pearson et al., Phys. Rev. A 73, 032307 (2006)
[3] S. Seidelin et al., Phys. Rev. Lett. 96, 253003 (2006)
[4] Kenneth R. Brown et al., Phys. Rev. A 75, 015401 (2007)
[5] D. Kielpinski et al. Nature 417, 709 - 711 (2002)
[6] U. Tanaka et al. Appl. Phys. B 81, 795-799 (2005)

Sideband cooling and coherent dynamics
in a microchip multi-segmented ion trap
Contribution 1
St. Schulz 1 , U. Poschinger 1 , F. Ziesel 1 , G. Huber 1 , F. Schmidt-Kaler 1
1 Universität Ulm, Institut für Quanteninformationsverarbeitung,
Albert-Einstein-Allee 11, 89069 Ulm, Germany
Miniaturized multi-segmented linear ion traps are a promising architecture for
quantum information processing in a scalable way [1]. The miniaturization of linear
Paul traps allows partitioning the trap region in storage and processing regions
for qubits. The individual control of many qubits in different adjacent zones is
fundamental for the implementation of large-scaled quantum algorithms. The crucial
requirement for a scalable quantum processor is the fast qubit transport between
spatial separated trap regions.
We present a novel scalable microchip multi-segmented ion trap with two different
adjacent zones, one for the storage and another dedicated for the processing
of quantum information using single ions and linear ion crystals: A pair of radiofrequency
driven electrodes and 62 independently controlled DC electrodes allow
shuttling of single ions or linear ion crystals with numerically designed axial potentials
at axial and radial trap frequencies of a few MHz [2]. We characterize the trap
using sideband spectroscopy on the narrow S 1/2 ↔ D 5/2 transition of the 40 Ca + ion,
demonstrate coherent Rabi rotations, Ramsey spectroscopy, optical ground state
cooling and determine the heating rate [3].
Recently we succeeded in combining sideband spectroscopy with a single ion transport
along the trap axis: Initially held and Doppler cooled in the loading region, the
ion is shuttled to a different trap region where we perform sideband spectroscopy.
Shuttled back, we reveal the ions quantum state from a fluorescence measurement.
Such operations are necessary for subsequent two-qubit quantum logic operations.
The applicability of our trap for scalable quantum information processing is proven.
References
[1] Kielpinski et al., Nature 417, 709 (2002).
[2] Schulz et al., Fortschr. Phys. 54, 648 (2006).
[3] Schulz et al., NJP, in press April 2008.
1

Controlling the Motion of Small Numbers of Ions in a Penning Trap
D. Crick, S. Donnellan, H. Ohadi, I. Bhatti, R.C. Thompson and D.M. Segal,
Imperial College London
We are studying Ca + ions held in a Penning trap with a view to applications in
quantum information processing (QIP) and the study of quantum mechanical phase
transitions. Results demonstrating laser cooling and observation of individual calcium
ions in a Penning trap will be presented. We have previously suggested a scalable
approach to QIP using ions in multiple miniature Penning traps, which involves
moving ions from one trap to another in a controlled manner [1]. The traps involved
are made by depositing arrays of ‘pad’ electrodes onto a pair of opposing planar
substrates. We report the design, construction and operation of a prototype array, with
three trapping zones, made from vacuum compatible circuit board. The next step is to
demonstrate the controlled movement of ions between the traps. Of relevance to
future work on quantum phase transitions we also report recent work with small
numbers of ions held in a conventional 3D Penning trap. We show that we are able to
trap, cool, image and manipulate the shape of very small ensembles of ions
sufficiently well to produce two-ion ‘Coulomb crystals’ aligned along the magnetic
field of a Penning trap. Images are presented which show the individual ions to be
resolved in a two-ion ‘crystal’. A distinct change in the configuration of such a
structure is observed as the experimental parameters are changed [2].
[1] J. R. Castrej´on-Pita, H. Ohadi, D. R. Crick, D. F. A. Winters, D. M. Segal, and R.
C. Thompson. ‘Novel Designs for Penning Ion traps’. J. Mod. Opt. 54, 1581–1594,
2007.
[2] D. R. Crick, H. Ohadi, I. Bhatti, R. C. Thompson, and D. M. Segal. ‘Two-ion
Coulomb crystals of Ca + in a Penning trap’, Optics Express, Vol. 16, Issue 4, pp.
2351-2362 (2008).

QUANTUM INFORMATION

Quantum information with Strontium ions at the Weizmann Institute
Nitzan Akerman, Shlomi Kotler and Roee Ozeri
The Weizmann institute of science, physics of complex system department
Rehovot, Israel.
Abstract
We at the Weizmann institute, Israel, are engaged in the construction of a new ions
trapping lab for quantum information experiments. We are using Strontium 88 atoms
which are ionized by two stage photonionization scheme and trapped using a linear
Paul trap made of tungsten needles. Since 88 Sr has no nuclear spin, the qubit will be
encoded into the Zeeman levels of the 5S 1/2 manifold. Due to the qubit sensitivity to
magnetic noise, an active feedback system is applied to compensate for such noise to
the micro Gauss regime (@50Hz). The detection of up/down state is aided by a
shelving scheme into the D5/2 using a narrow width (sub kilohertz) laser, to be
constructed.

Cavity QED and Cavity Mediated Cooling Using Ion
Coulomb Crystals
M.Albert, J.P.Marler, P.F.Herskind,A.Dantan,
M.B.Langkilde-Lauesen and M.Drewsen
Institute of Physics and Astronomy, University of Aarhus,
Ny Munkegade, Building 520, DK-8000 Aarhus C, Denmark
E-mail: malbert@ifa.au.dk
Clouds of cold ions represent an interesting alternative system to a single
atom/ion for studying CQED effects. When a trapped cloud of ions is cooled
below a certain critical temperature (≈mK), the ions form a spatially ordered
state, refered to as an ion Coulomb crystal.
These ion Coulomb crystals can be easily trapped and cooled in sufficient
number to potentially access the interesting regime where the cooperativity
parameter, C = g2 N
, is greater then one and the collective coupling g√ N
2κγ
exceeds both the spontaneous decay rate, 2γ, and the cavity decay rate,
κ, without using extremely high finesse cavities (g is the single atom-field
coupling parameter, N the number of atoms in the cavity mode).
In our setup, photoionisation allows the controlled isotope selective loading
of ion Coulomb crystals of arbitrary size (10-10000 ions) into a linear Paul
trap. Our high finesse cavity (κ ≈ 2 MHz) is mounted co-linear with the trap
axis and provides good overlap of the cavity mode with the Coulomb crystal.
We will present recent experimental results which indicate that the number of
40 Ca + ions inside the cavity mode of our experimental setup is high enough
to achieve strong collective coupling, together with the first indications of
collective coupling of the ion Coulomb crystal to the cavity field.
Beside near-future CQED experiments, opportunities to use our system to
further cool the ion crystals by cavity mediated cooling schemes are discussed.
1

The Dirac Equation in Trapped ions
A. Bermudez
Departamento de Física Teórica I, Universidad Complutense, 28040. Madrid, Spain.
We develop a novel quantum optical perspective into a couple of quantum relativistic systems: First we show
how the two-dimensional extension of the harmonic oscillator, known as the Dirac oscillator, can be exactly mapped
onto a chiral Anti-Jaynes-Cummings model of quantum optics. This equivalence allows us to predict a series of
novel relativistic phenomena, such as spin-orbit Zitterbewegung. Furthermore, we also make a realistic experimental
proposal, at reach with current technology, for studying the equivalence of both models using a single trapped ion
[1]. Second, we show that a relativistic version of Schrödinger cat states, here called Dirac cat states, can be built in
relativistic Landau levels when an external magnetic field couples to a relativistic spin 1/2 charged particle. Under
suitable initial conditions, the associated Dirac equation produces unitarily Dirac cat states involving the orbital
quanta of the particle in a well defined mesoscopic regime. These states have a purely relativistic origin and cease to
exist in the non-relativistic limit [2].
[1] A. Bermudez , M. A. Martin-Delgado, E.Solano, Phys. Rev. A. 76, 041801(R) (2007).
[2] A. Bermudez, M. A. Martin-Delgado, E.Solano, Phys. Rev. Lett. 99, 123602 (2007)

Generation of relative-intensity squeezed light using four-wave mixing
in an rubidium atomic vapor
Q. Glorieux, ∗ R. Dubessy, B. Dubost, S. Removille, T. Coudreau,
S. Guibal, L. Guidoni, J.P. Likformann, and N. Sangouard
Laboratoire Matériaux et Phénomènes Quantiques,
CNRS UMR 7162 et Université Denis Diderot, Paris
P. Milman
Laboratoire de PhotoPhysique Moléculaire du CNRS, Université Paris-Sud XI
In order to test a quantum memory in the continuous variables regime, based on trapped Sr +
ions, we have started an experiment to produce relative-intensity squeezed light. We plan to store
the information contained in the quadratures of light beams on the quadratures of an observable of
an ensemble of ions. In particular, we plan to use non classical states (intensity correlated beams) [1].
Four-wave mixing (4WM) is one among the different technique used to produce quantum correlated
beam. The advantages of this technique are the large level of squeezing possible, and the simplicity
of the set-up compared to OPOs based methods. We are starting an experiment based on the work of
[2] who have obtained 8dB of relative-intensity squeezing at 795nm in a vapor of rubidium atoms. We
are also working on a model based upon the Heisenberg-Langevin approach [3] to find the optimal
parameters.
For our application with an ion cloud of Sr + , we need to transpose this experiment to S 1/2 → P 1/2
transition at 422nm. Hopefully, rubidium has an atomic transition at a wavelength close to the one
of Sr + , and we will be able to use a rubidium atomic vapor to produce relative-intensity squeezed
beams at 422nm.
We describe in the poster the experimental setup, our first results at 795nm and summarize our
theoretical developments.
[1] T. Coudreau, F. Grosshans, S. Guibal, L. Guidoni, Feasibility of a quantum memory for
continuous variables based on trapped ions : from generic criteria to practical implementation.
J. Phys. B : At. Mol. Opt. Phys., vol. 40 (2) pp. 413-426 (2007)
[2] C. F. McCormick, V. Boyer, E. Arimondo, and P. D. Lett, Strong relative intensity squeezing by four-wave
mixing in rubidium vapor for light, Opt. Lett. 32, 178-180 (2007)
[3] L. Davidovich Sub-Poissonian process in quantum optics Rev. Mod. Phys., Vol 68, No 1, (January 1996)
∗ Electronic address: quentin.glorieux@univ-paris-diderot.fr

From a single-photon emitter to a single ion laser
Authors: Helena G. Barros 1,2 , François Dubin 1 , Carlos Russo 1,2 , Andreas Stute 1,2 , Piet O.
Schmidt 1 , and Rainer Blatt 1,2 — 1 Institut für Experimentalphysik, Universiät Innsbruck,
Technikerstr. 25, A-6020 Innsbruck — 2 Institut für Quantenoptik und Quanteninformation,
Österreichische Akademie der Wissenschaften, Otto-Hittmair-Platz 1, A-6020 Innsbruck
A single atom interacting with a single mode of a cavity is the building block of a laser
from a fundamental point of view. In this work, we study a single 40 Ca + ion coupled to a high
finesse optical resonator. In particular, we evaluate the statistical properties of emitted cavity
photons for different regimes of operation.
In the experiment, a drive laser together with an optical cavity excites an off-resonant
Raman transition that connects the S 1/2 and D 3/2 levels of the 40 Ca + ion. Population gets
transferred from S 1/2 to D 3/2 while emitting a photon into the cavity. The excitation cycle is
closed by a recycling laser that brings the atomic population back to the initial state S 1/2 via
resonant excitation of the P 1/2 state. The photons leave the cavity at a rate of 54 kHz and are
sent to a Hanbury-Brown & Twiss setup, where photon-photon correlations are measured. For
weak recycling laser intensity, the system is operating as a single-photon source. In this
regime, we can tune the statistics of the photon arrival times from sub-Poissonian to super-
Poissonian behaviour. For faster recycling rates, we observe a single-atom laser at threshold.

Quantum phases of the frustrated nearest-neighbor XY
model on the anisotropic triangular lattice
P. Hauke, R. Schmied, T. Roscilde, V. Murg, D. Porras, and J. I. Cirac
With the help of exact diagonalization, projected entangled pair states (PEPS),
spin wave, and modied spin wave theory we analyze the ground state of the frustrated
nearest-neighbor XY model on the anisotropic triangular lattice [1]. As
summarized in the gure below, we nd that the transition from the 1D gapless
spin-liquid phase to the 2D spiraling ordered phase passes through a gapped
spin-liquid phase, similar to what has been predicted for the same model with
Heisenberg interactions [2]. Further, a second gapped spin-liquid phase marks the
transition to the 2D Néel-ordered phase. We propose that the evolution from a
1D gapless spin liquid to a spiraling ordered state, and from spiral to Néel order,
acquires a `universal' discontinuous structure: instead of a continuous deformation
of correlations in the ground state, exhibited by the classical system, the quantum
system rst shows a complete loss of (quasi-)long-range correlations in favor of
a short-range spin-liquid state, and then a revival of correlations at a dierent
wavevector.
We propose a setup for quantum simulation of this frustrated nearest-neighbor
XY model on the anisotropic triangular lattice. The vibrational degrees of freedom
of trapped ions may be mapped to a spin-1/2 system due to the strong
anharmonicity induced by an optical lattice potential. These eective spins couple
via the dipoledipole component of the Coulomb interaction between the ions,
which falls o as the third power of distance. By adjusting the spatial direction
of vibration, the anisotropy of the dipoledipole interaction can be tuned over a
sucient range. This scheme may easily be extended to other geometries.
references:
[1] R. Schmied, T. Roscilde, V.
Murg, D. Porras, and J. I. Cirac,
arXiv:0712.4073v2 [cond-mat.str-el]
[2] S. Yunoki and S. Sorella, Phys. Rev.
B 74 014408 (2006)
1

Trapped Ion Cavity-QED:
Interfacing Ions and Photons
P. Blythe, A. Mortensen, N. Seymour-Smith, M. Keller and W. Lange
University of Sussex
Miniature cavity-QED systems are a versatile tool for many applications
in quantum information processing, ranging from the exchange of quantum
informations between nodes of a quantum network to the entanglement of
multiple atoms by means of intra-cavity photon exchange. We investigate
different schemes taking advantage of the precise control of the ions’ motional
and internal degrees of freedom.
Deterministic entanglement of ions and photons and the mapping of their
respective quantum states allows for a bidirectional transfer of quantum information
over long distances. A crucial element in such a transfer is the
deterministic generation of single photons from a single atom, which we have
achieved using a 40 Ca + -ion stored in a radio-frequency trap in the Lamb-
Dicke regime. As we have demonstrated, single photons can be extracted
from the ion continuously over times on the order of hours. We have recently
improved our set-up by implementing a novel miniature ion-trap system allowing
for much shorter cavities. This enhances the coherent coupling between
the ion and the cavity mode, reaching the regime of strong coupling.
The trap comprises three sandwiched layers of copper electrodes, insulated
by kapton spacers. Optimal alignment is provided by machining each layer
from a single sheet, separating the individual electrodes after fixing their position.
Apart from deterministic schemes we are also investigating probabilistic entanglement
methods. We have developed a scheme to entangle two ions coupled
to the same cavity by detecting two coincident photons emitted from
the cavity with orthogonal polarisation. In this case, the constraints on the
coherent coupling are more relaxed and therefore larger cavities can be used.
We have developed an ion-trap cavity system which is especially suited for
this application.

Towards a Quantum memory in trapped ions
S. Removille, ∗ R. Dubessy, Q. Glorieux, T. Coudreau, S.
Guibal, L. Guidoni, J.P. Likforman, and N. Sangouard
Laboratoire Matériaux et Phénomènes Quantiques,
CNRS UMR 7162 et Université Denis Diderot, Paris
Trapped ions constitute a choice material for quantum information, and in particular for the realization
of quantum memories. Such a memory will be of particular importance in order to implement
long-distance quantum communication networks.
Quantum information can be stored and manipulated in systems containing a small number of
particles (discrete variables regime) as well as in much larger systems (continuous variables regime).
In the continuous variables regime, one seeks to store the information contained in the quadratures
of a polarized light beam on the observables defined on an ensemble of atoms or ions. This has already
been achieved using a cloud of cesium atoms at room temperature [1]. However important issues have
still to be reached such as increasing the storage time which is now on the order of the millisecond. We
have shown that one can in principle implement with trapped and cooled ions a quantum memory
which allows for the a posteriori measurement of an arbitrary quadrature with storage times of
several seconds [2]. These long storage times can be explained by the absence of the most common
sources of decoherence, namely collisions, finite interaction time and dephasing effects due to stray
magnetic fields.
We are developing an experimental setup devoted to store quantum information in a cloud of cold
trapped ions. We have already trapped up to 10 4 Sr + ions in a large linear Paul trap. The ions are
slown down using Doppler laser cooling. We retrieve the fluorescence of the cloud on a CCD camera
and the reached temperature is on the order of 100mK. We have recently settled a photoionisation
system that enables us to load the trap in a low heating rate regime, reaching lower temperatures in
large clouds. We will describe in the poster the experiments carried out to obtain a well controlled
cloud of cold ions.
[1] B. Julsgaard, J. Sherson, J.I Cirac, J. Fiurášek, E.S. Polzik, ”Experimental demonstration of quantum
memory for light”, Nature 432, 482 (2004)
[2] T. Coudreau, F. Grosshans, S. Guibal, L. Guidoni, Feasibility of a quantum memory for continuous
variables based on trapped ions J. Phys. B, 40, 2 (2007)
∗ Electronic address: sebastien.removille@univ-paris-diderot.fr

Towards two-dimensional quantum simulations with trapped ions
Christian Schneider † , Robert Matjeschk, and Tobias Schaetz
Max-Planck-Institut fuer Quantenoptik, Garching, Germany
An ion crystal in a Paul trap is a promising candidate for a quantum simulator or analogue
quantum computer. Thereby a quantum system shall be implemented and studied which is
described by the same Hamiltonian as the system to be simulated. The crucial parameters of
the implemented system are accessible which is often not the case for the “real” sytem. First
experimental results in building a quantum simulator for a Quantum Ising Hamiltonian with
two ions have recently been shown [1].
To gain deeper insight into quantum dynamics, we plan to extend these fundamental experiments
to more ions and into two dimensions [2]. As successful studies of one-dimensional planar
Paul traps have been shown [3,4], a promising approach is to realize a two-dimensional array
of trapped ions in a planar two-dimensional surface trap. We want to show our visions of twodimensional
quantum simulations and first steps towards their realization by a two-dimensional
Paul trap of 2 × 2 ions.
[1] A. Friedenauer, H. Schmitz et al., arXiv 0802.4072v1, 1-6
[2] T. Schaetz et al., J. Mod. Opt. 54, 2317–2325
[3] J. Chiaverini et al., Quant. Inf. Comp. 5, 419–439
[4] S. Seidelin et al., Phys. Rev. Lett. 96, 253003–4
† mailto:christian.schneider@mpq.mpg.de

Trapped Barium Ions for Quantum Computation, Atomic Clock and
Precise Measurement
G.Shu, N.Kurz, M.Dietrich, A.Kleczewski, G.Howell, R.Bowler, J.Salacka, P.Green,
B.B.Blinov
Department of Physics, University of Washington
Abstract
This poster presents the research at University of Washington centered around single trapped
barium ions. Single-ionized odd isotope of barium( 137 Ba + ) is an excellent candidate for hyperfine
qubit. Its ground state splits into two hyperfine levels 8GHz apart with almost infinite
lifetime and long coherence, thus making it an excellent choice for qubit states. We show the
schemes of qubit initialization, detection and manipulation in this poster.
A single photon source based on ultrafast pulse driven Barium ion is also under developing.
Besides simple structure and high repetition rate, it can also bridge the static qubits(ions) with
flying qubits(photons) and make remote entanglement of photons and atoms possible, which is
desirable for quantum computation and communication.
Single Barium ion is also a nice platform for precise atomic measurements and optical clocks.
Efforts are made to build a frequency reference based on 138 Ba + ’s 6S 1/2 ↔ 5D 3/2 dipole forbidden
transition. Besides its extremely narrow natural line width (5D 3/2 ’s lifetime is 80s),
another attractive property is its insensitivity to quadruple electric field which is one of the main
sources of systematic error in a quadruple trap. The progress of this work is also presented in
this poster.
1

Quantum imaging with trapped ions
*J. von Zanthier 1 , Ch. Thiel 1 , Th. Bastin 2 , G. S. Agarwal 3
1
Institut für Optik, Information und Photonik, Universität Erlangen-Nürnberg, Staudtstrasse 7/B 2, D - 91058 Erlangen, Germany
2
Institut de Physique Nucléaire, Atomique et de Spectroscopie, Université de Liège au Sart Tilman, Bât. B15, B - 4000 Liège, Belgium
3Department of Physics, Oklahoma State University, Stillwater, OK 74078-3072, USA
1
Phone: ++49 (0)9131 85 27603, 1 Fax: ++49 (0)9131 85 27293, *Email: jvz@optik.uni-erlangen.de
We propose to employ photons emitted from single trapped ions to image a physical
object of sub-wavelength size with 100% contrast by making use of joint detection
probabilities.
In quantum imaging, so far sub-classical spatial resolution has been achieved with 100 % contrast using
entangled photons in combination with multi-photon absorbers [1,2]. In addition, it has been shown that
using thermal light together with single photon detection enables to obtain sub-classical resolution, too,
however with a contrast reduced to less than 50% [3]. Recently, we proposed a scheme achieving a spatial
resolution of λ/N with 100 % contrast involving initially uncorrelated and incoherent photons
spontaneously emitted from N equidistant single photon sources, e.g. trapped ions, and subsequently
detected by N detectors in the far field [4]. For certain detector positions r2,…, rN, it was shown that the
Nth order correlation function as a function of r1 takes the form 1 + cos N δ(r1) resulting in a fringe
spacing given by λ/N. With δ(r) = k d sinθ(r) being the optical phase difference of photons emitted from
adjacent sources involving the source distance d, the scheme, however, is limited to provide information
only about the spatial distribution of the source itself.
Here we propose to image a distinct physical object, e.g., an aperture, with sub-wavelength resolution
and a contrast of 100% using the N single photon emitters as a light source in an ordinary far-field
imaging scheme. An equal number of detectors as emitters - positioned in the far-field of the object -
perform correlation measurements of the emitted photons that pass by the object (see fig. 1). We show
that it is possible by exploiting quantum interferences between the different quantum paths of the
photons to image and resolve the object with a resolution of λ/N.
In case of a single aperture (of height a) and two 2-level ions used in a pulsed regime as single photon
sources, the setup is shown below (see fig. 1). In a successful measurement cycle, the two ions at R1 and
R2 each emit a single photon which both pass by the aperture - positioned in the far-field of the ions - and
are recorded by two detectors in the far-field of the aperture at r1 and r2. Using standard far-field
approximations and limiting the calculation to the x-z-plane the joint two photon detection probability is
given for|r2x| = r1x , R1x = 0 and R2x = πRz/(ka) by
G(2)( r1x) ~ sin 2 (2 δ(r1x))
This function oscillates twice as fast as the classical intensity diffraction pattern I(rx) ~ sin 2 (δ(rx)) obtained
conventionally with as single detector when recording diffracted classical light in the far-field of the
aperture (see e.g. [5]). According to Abbe’s criterion of resolution this implies that sufficient information
is available to image and resolve the aperture even if of heigth a = λ/2 (see fig. 2). In particular, for r2x = r1x

and using a two-photon absorbing medium placed in the image plane it is possible to image an aperture
of sub-wavelength size using an optical lens.
R 1
x
y
z
r 1
R 2
r 0
|e
0
b
a
r 2
|g
Figure 1: Far-field imaging scheme achieving sub-wavelength
resolution: Two single photon emitters, e.g. two trapped 2-level
ions, are used as a source to irradiate and image a physical object,
here a rectangular aperture of height a. The measurement can be
either performed in the Fourier plane or in the image plane using
an optical lens.
Figure 2: Classical intensity diffraction pattern vs. second order
correlation signal for the system shown in fig. 1. According to
Abbe’s criterion an object can be imaged and resolved if at
least the first order diffraction maxima are visible in the
Fourier plane. According to this criterion the minimum
distance that can be imaged and resolved in a classical setup is
of the order of the wavelength λ (see e.g. [6]). By contrast, the
minimum distance resolvable with the setup shown in fig. 1 is
of the order of λ/2.
References
[1] A. N. Boto et al., Phys. Rev. Lett. 85, 2733 (2000)
[2] M. D'Angelo, M. V. Chekhova, Y. Shih, Phys. Rev. Lett. 87, 013602 (2001)
[3] G. Scarcelli, A. Valencia, Y. Shih, Europhys. Lett. 68, 618 (2004)
[4] C. Thiel, T. Bastin, J. Martin, E. Solano, J. von Zanthier, G. S. Agarwal, submitted for publication
[5] M. Born and E. Wolf, Principles of Optics (Pergamon Press, New York, 1980), 6th ed.

Towards ion trap array architectures with 171Yb+ ions
James J. McLoughlin, Altaf H. Nizamani, James D. Siverns, Robin C. Sterling,
Merlin Bevan-Stevenson, Nicholas Davies, Jessica Grove-Smith, Marcus Hughes,
Ben Johnson, Kieran Lee, Ben S. Pruess, Rajiv Ramasawmy, David N. Scrivener,
Tim Short, and Winfried K. Hensinger
Department of Physics and Astronomy, University of Sussex, Falmer, Brighton, BN1 9QH, UK
We present experimental progress towards trapping171Yb+. The experiments are directed towards
scaling the ion trap quantum computer via advanced shuttling operations inside sophisticated ion trap
arrays. Ytterbium is one of the most suitable elements for quantum information processing (QIP) because
of its simple atomic structure and accessible transitions.
A number of lasers have been built for the experiment. Ionisation will be achieved via two photonionisation
using 399 nm photons. Following ionisation, cooling will be accomplished using the 369 nm
2S1/2 (F=1) -2P1/2 (F=0) dipole transition. Atoms can also decay into a low lying D-state as well
as a 2F7/2 state (via collisions). To complete the cooling cycle, 935nm and 638nm re-pumping beams
are applied. Off-resonant transitions to undesired hyperfine levels will also occur and repumping occurs
via sideband excitation, with sidebands being generated via high frequency electro optic modulators
and laser diode current modulation. Most lasers are in-house built external cavity diode lasers with
exception of 369nm which is a frequency doubled laser. In order to maintain cooling and re-pumping it
is vital the lasers are frequency locked. The locking scheme we have implemented consists of a 780nm
laser that is locked to a rubidium atomic reference vapour cell. All other lasers are locked to this laser
via a transfer cavity lock. This consists of a scanning Fabry-Perot cavity where the fringe separation
between different wavelengths is held constant via computer controlled feedback to the individual lasers.
This effectively drift stabilizes our laser sources to the rubidium atomic reference. Labview is being
employed to measure the separation of different lasers during the cavity scan and to calculate the ratio
of their peak separations. The result of this will produce an error signal that indicates the drift of each
laser, whilst being independent of any thermal drift of the cavity.
We will also describe our design and studies of radio-frequency application for ion traps, in particular,
how to build helical resonators with high Q-factors. We have experimentally studied how different
design parameters affect the Q-factor.
A versatile vacuum system has been designed to cater for a wide variety of ion trap chips. With
over 100 electrical connects the system will be able to host large ion trap arrays, and multiple optical
access ports and atomic ovens support both symmetric and asymmetric traps. The design is optimized
for fast trap turn-around times.
Figure 1: Versatile vacuum system for
the operation of advanced ion trap chips.
Red lines show optical access making this
system suitable for both symmetric and
asymmetric trap structures. The vacuum
systems hosts a chip carrier with
100 electrical interconnects.
We present an overview of the whole ion trapping experiment, including the design of the first ion
trap and the imaging system.
We have also developed a method to efficiently simulate the electric fields of novel ion trap geometries
using the Boundary element simulation method and we will present first results.

METROLOGY

The 88 Sr + OpticalFrequencyStandardattheNational
ResearchCouncil
PierreDubé,AlanA.Madej,andJohnE.Bernard
InstituteforNationalMeasurementStandards,
NationalResearchCouncil,Ottawa,ON,CanadaK1A0R6
E-mail:pierre.dube@nrc-cnrc.gc.ca
Analmostidealfrequencyreferencecanberealizedwithalaser-cooledsingleionconfinedinan
rfquadrupoletrap[1]. AttheNationalResearchCouncilofCanadawehavedevelopedanoptical
frequencystandardbasedonthe 88 Sr + ion.
Inourpresentsystem,asingle 88 Sr + ionisconfinedinanrfPaultrapandiscooledwithdiodelaser
radiationusingthe5s 2 S 1/2 −5p 2 P 1/2 transitionat422nm.Thefrequencyofthislaserisreferencedto
asaturatedabsorptionlinein 85 Rbforaccuratedetuningfromthecoolingtransitionlinecenter[2].In
addition,apolarization-scrambledlaserat1092nmisrequiredduringthecoolingperiodtoprevent
decayoftheiontothemetastable 2 D 3/2 state.Thereferencefrequencyin 88 Sr + isthe0.4Hzwide
5s 2 S 1/2 –4d 2 D 5/2 transitionat445THz(674nm).Itscenterfrequencyisprobedwithanultra-stable
andnarrow674nmdiodelasersystem.Thestabilityoftheprobelaserisprovidedbyahighfinesse
referenceresonator(F =160000)whichisentirelymadeofultra-lowexpansioncoefficientglass
(ULE). Itishousedinavibrationisolatedvacuumchamberthatisstabilizedatthetemperatureof
zerothermalexpansioncoefficientoftheULEforoptimalstability. Linewidthsof5Hzhavebeen
observedontheS–Dclocktransition.
Duringthepastfewyears,thedemonstratedaccuracyofopticalfrequencystandardshasimproved
bymorethanoneorderofmagnitudefollowingthedevelopmentofthefemtosecondlaserfrequency
comb.Thistechnologyhasgivenustheopportunitytomakeadetailedstudyofthefrequencyshifts
asafunctionofthequantizationaxisdirectionthatledtoasimpletechniqueforthecancellationofthe
electricquadrupoleshiftandofthetensorpartoftheStarkshift[3].Theelectricquadrupoleshifthas
itsoriginintheinteractionbetweenthequadrupolemomentoftheclocktransitionandtheresidual
electricfieldgradientcausedbypatchpotentialsonthetrapelectrodes;itisoneofthemostimportant
systematicshiftslimitingtheaccuracyofseveralsingleionfrequencystandards.Thistechniquehas
beenusedtomakethemostaccuratefrequencymeasurementwiththe 88 Sr + iontodate[4]. An
overviewofourexperimentalsetupusedtorealizethe 88 Sr + opticalfrequencystandardandrecent
resultswillbepresentedattheworkshop.
References
[1] H.G.Dehmelt,“Mono-ionoscillatoraspotentialultimatelaserfrequencystandard,”IEEETrans.Instrum.
Meas.,vol.IM-31,pp.83–87,1982.
[2] A.D.Shiner,A.A.Madej,P.Dubé,andJ.E.Bernard,“AbsoluteopticalfrequencymeasurementofsaturatedabsorptionlinesinRbnear422nm,”Appl.Phys.B,vol.89,pp.595–601,2007.
[3] P.Dubé,A.A.Madej,J.E.Bernard,L.Marmet,J.-S.Boulanger,andS.Cundy,“Electricquadrupoleshift
cancellationinsingle-ionopticalfrequencystandards,”Phys.Rev.Lett.,vol.95,p.033001,2005.
[4] H.S.Margolis,G.P.Barwood,G.Huang,H.A.Klein,S.N.Lea,K.Szymaniec,andP.Gill,“Hertz-level
measurementoftheopticalclockfrequencyinasingle 88 Sr + ion,”Science,vol.306,pp.1355–1358,2004.

Towards Direct Frequency Comb Spectroscopy using Quantum Logic
Borge Hemmerling, Lukas An der Lan, Piet O. Schmidt
Institut fur Experimentalphysik, Universitat Innsbruck, Austria
A possible change of the ne-structure constant over cosmological time scales
derived from quasar absorption lines is currently strongly debated. One of the
diculties turns out to be the lack of precise laboratory data on transition lines
of elements with a complex level structure such as Ti + and Fe + [1].
We challenge this problem by developing a versatile experimental setup in
which spectroscopy ions are sympathetically cooled by magnesium ions in a
linear Paul trap. Using quantum logic techniques, initial state preparation and
state detection of the spectroscopy ion can be very ecient. Owing to the
complex level structure of these spectroscopy ions, repumping from unwanted
states is required. We plan to implement this by applying an appropriately
tailored optical frequency comb.
We will present the latest status of our experimental setup and simulation
results on the expected uorescence signal from a Ca + test candidate. We
furthermore present schemes based on quantum logic techniques to interrogate
single ions in order to further improve the accuracy of the spectroscopic data.
[1] J. C. Berengut, V. A. Dzuba, V. V. Flambaum, M. V. Marchenko and J.
K. Webb, arXiv:physics/0408017 (2006)
1

H 2 + vibrational spectroscopy : theoretical results and experimental
developments
Jean-Philippe Karr, Vladimir I. Korobov*, Jofre Pedregosa, Franck Bielsa,
Albane Douillet and Laurent Hilico
Laboratoire Kastler Brossel, UEVE, UPMC, ENS, CNRS
Université d’Evry Val d’Essonne, Département de Physique
boulevard F. Mitterrand, 91025 Evry
E-mail :jean-philippe.karr@univ-evry.fr
*Joint Institute for Nuclear Research, 141980, Dubna, Russia
We develop a project aiming at direct optical determination of the proton to electron mass ratio with a
relative accuracy in the 10 -10 range. It relies on Doppler free two-photon spectroscopy of H 2 + ions. Indeed,
H 2 + ro-vibrational levels mainly depend on the Rydberg constant (known with a 6.6 x 10 -12 relative accuracy)
and on m p /m e (4.3 x 10 -10 ). It also relies on the accurate ab-initio calculation of H 2 + energy levels at the 10 -10
level.
Because H 2 + is a homonuclear molecular ion, all bound ro-vibrational levels are metastable and all onephoton
transitions between them are prohibited. Nevertheless, ro-vibrational levels with v ≥ 1 can be
photodissociated by 248 nm UV photons (v is the vibrational quantum number).
Doppler-free two-photon transitions in the infra-red domain (9-10 µm) are allowed and can be observed
using 2 IR +1 UV ’ resonance enhanced multi-photon dissociation (REMPD) as shown in Fig. 1.
From the theoretical point of view, the poster presents H 2 + ro-vibrational structure, two-photon transitions
intensities (in atomic units in Fig. 2) and recent progress in radiative and relativistic corrections and
hyperfine structure calculations, with a present accuracy level of 3 x 10 -10 .
The experimental set-up first aims at probing the (v=0,L=2)→(v=1,L=2) two-photon transition where L
is the total orbital angular momentum. The infra-red laser source is a quantum cascade laser (QCL) phaselocked
to a HCOOH stabilized CO 2 laser. We present the spectral features of the QCL source (53 mW
optical power, kHz linewidth, GHz tunability) as well as the injection in a high finesse Fabry-Perot cavity,
and discuss the expected two-photon transition yield.
The hyperbolic ion trap and photodissociation detection process are presented in another poster.
Fig 1:
Fig 2 :
References:
• http://physics.nist.gov/cuu/index.html
• L. Hilico, N. Billy, B. Grémaud, D. Delande, J. Phys. B 34, 491-507, (2001)
• J.-Ph. Karr, S. Kilic, L. Hilico, J. Phys. B 38, 853-66 (2005)
• V.I Korobov, L. Hilico, J-Ph. Karr, Phys. Rev. A 74, 040502(R)/1-4 (2006)
• J.-Ph. Karr, F. Bielsa, T. Valenzuela Salazar, A. Douillet, L. Hilico, V. I. Korobov, Can. J. Phys 85, 497-507 (2007)
• V.I. Korobov, Phys. Rev. A. 77, 022509 (2008).
• J.-Ph. Karr, F. Bielsa, A. Douillet, J. Pedregosa, V.I. Korobov and L. Hilico, to be published in Phys. Rev. A.
Vibrational spectroscopy of H 2 + : hyperfine structure of two-photon transitions.
• J.-Ph. Karr, V.I. Korobov and L. Hilico, to be published in Phys. Rev. A. Vibrational spectroscopy of H 2 + : precise
evaluation of the Zeeman effect

Two photon ro-vibrational spectroscopy of H 2+ : From Hyperbolic to Linear RF trap
J. Pedregosa Gutierrez, F. Bielsa, J-P. Karr, A. Douillet and L. Hilico
Laboratoire Kastler Brossel, UEVE, UPMC, ENS, CNRS
Université d'Evry Val d'Essonne, Département de Physique
boulevard F. Mitterrand, 91025 Evry
e-mail: pedregosa@spectro.jussieu.fr
Abstract
Experiments to obtain precise and reliable values of fundamental constants sometimes reaches such
a level of complexity that they are only realized a single time, by a single research group. In
particular, this is the case for the current accepted value of the proton mass [1], m p and the electron
mass [2], m e , from which the ratio m e /m p can be deduced with a 4.3×10 −10 relative accuracy. For this
reason, we are developing an experiment which will provide an independent measurement of m e /m p
by performing two-photon Doppler free ro-vibrational spectroscopy if H 2
+
ions[3]. This technique is
expected to improve the relative accuracy to the 1×10 −10 level. In order to achieve this goal, tunable
and stable laser sources[4, 5] and trapped ions are required. The present poster will concentrate in
this second aspect of the set-up. In particular, the current status and performance of our hyperbolic
trap will be presented as well as the design for an upgrade of the system, which includes the
development of a linear Paul trap (LPT). Through ion dynamic simulations we have obtain obtain
an estimation of the ion cloud distributions for the hyperbolic and linear traps. A scheme of ion
extraction for the LPT perpendicular to the trap axis has been demonstrated to be highly efficient
(~80%) using simulations.
Figure 1: Linear trap and optical bench
Ref.
[1] Van Dyck et al., Phys. Rev. Lett, 75, 3598 (1995)
[2] G. Werth et al., Phys. Rev. Lett. 85, 011603 (2002)
[3] L. Hilico et al., J. Phys. B : At. Mol. Phys, 34, 1 (2001)
[4] F. Bielsa et al., Opt. Lett., 32, 1641 (2007)
[5] See as well the other poster of our group: “H 2
+
vibrational spectroscopy: theoretical results and experimental
developpements”

Broadly tunable sub-mW CW Narrowband mid-IR Laser Source for
Molecular Spectroscopy
Sergey Vasilyev, Stephan Schiller, and Alexander Nevsky
Institute for Experimental Physics, Universitätsstr 1, 40225 Düsseldorf, Germany
Arnaud Grisard, David Faye, Eric Lallier
Thales Research and Technology, RD 128, 91767 Palaiseau cedex, France
Z. Zhang, A. J. Boyland, J. K. Sahu, M. Ibsen, W. A. Clarkson
Optoelectronics Research Centre University of Southampton Highfield, Southampton,SO17 1BJ
United Kingdom
The successful development of methods for cooling and trapping molecules is expected to lead
to a demand for appropriate continuous-wave laser sources allowing performing high-resolution
spectroscopy and internal state manipulation. One example is the search for parity violation
effects on the vibrational spectra of chiral molecules.
One spectral range of interest, so far not yet satisfactorily available, is the IR range beyond 4.5
µm. The objective of our research project is the development of a widely tunable (5 - 15 µm)
narrowband mid-IR laser source based on a nonlinear down conversion of 1.5 - 2.0 µm laser
radiation to mid-IR spectral region using difference frequency generation (DFG) and optical
parametric generation (OPO) in a Orientation-Patterned Gallium Arsenide (OP-GaAs) crystal.
The OP-GaAs crystal combines a high nonlinearity, wide transparency range, and high thermal
conductivity with merits of a quasi-phase-matching technique. Recently a method was developed
for fabrication of large-size OP-GaAs structures by a combination of molecular beam epitaxy
and hydride vapor phase epitaxy.
Tunable mid-IR source based on the DFG between a narrowband broadly tunable high power
EDFA (10 W, 1540-1570 nm) and thulium (Tm) doped fiber laser MOPA (1 W, 1945 nm) has
been developed. DFG output wavelength was tunable from 7.6 µm to 8.2 µm with pm precision
by tuning of the EDFA wavelength and the nonlinear crystal temperature. Mid-IR output power
of 0.5 mW has been measured. The measured characteristics of the OP-GaAs sample
demonstrate a high quality of the material
Spectroscopic capabilities of the mid-IR source were tested by measuring of CH 4 absorption
spectra. Objectives of further work are the development of 5 - 15 µm tunable narrowband fiber
laser pumped OP-GaAs OPO source. As one practical application outside the field of cold
molecules we can envision a DFG or OPO based compact multi-gas spectrometer for analysis of
polluting gases.

Design of a battery-based low noise voltage source
Anke Wagner 1 , Klaus Blaum 1,2,3 , Wolfgang Quint 2 , Birgit Schabinger 1 , Sven Sturm 1
1 Institut für Physik, Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
2
GSI Darmstadt, 64291 Darmstadt, Germany
3 Max-Planck-Institut für Kernphysik, D-69117 Heidelberg
Bound-state quantum electrodynamical (BS-QED) calculations can be tested by highprecision
measurements of the magnetic moment of the electron bound in highlycharged
ions [1]. Therefore it is planned to measure the g-factor of 40,48 Ca 17+,19+ ions
in a double Penning-trap [2,3]. To reach the precision aimed for (δg/g~10 -9 ), highly
stable voltage sources are needed to set the electrode-voltages. In order to eliminate
possible disturbance sources for these power supplies a very stable supply voltage is
required, which has to be independent of the electricity network in order to avoid
noise and ground loops. To this end, a battery-based voltage source was designed.
A single car-battery (12V) is used to generate the required output voltages (±15V,
±5V) and a maximum current per channel of 1.5A. The dc-voltage is converted into
ac-voltage by a sine-generator, amplified by a power amplifier and a transformer,
commutated by a bridge rectifier and, finally, flattened by a filter, a choke and voltage
controller. The voltage controller was also self-build, as no commercially available
controller was able to meet the requirements. It was aimed for a stability better than
10 -3 over the load and a noise floor exceeding the -120dBV/√Hz of a standard
precision voltage source. To control and monitor the voltages as well as the currents,
a microcontroller, connected to a PC, is used.
The noise floor of the voltage source was tested to -145dBV/√Hz for frequencies
below 30kHz and -155dBV/√Hz for frequencies above 30kHz, respectively. The long
term stability is 10 -5 or better. The obtained results and the present performance of
the battery-based voltage source will be presented.
[1] G. Werth et al., Int. J. Mass Spectrom. (2006)
[2] M. Vogel et al., Nucl. Inst. Meth. B 253, 7 (2005)
[3] B. Schabinger et al., Journal of Physics: Conf. Series 58 (2007) 121-124

Test of QED and CPT via g-factors
S. Kreim 1 , J. Alonso 1,2 , K. Blaum 1,2 , H.-J. Kluge 2 , W. Quint 2 , B. Schabinger 2 , S. Stahl 3 , S.
Ulmer 1 , J. Verdu 1 , M. Vogel 4 , J. Walz 1 , G. Werth 1
1 Johannes Gutenberg University, Institut fuer Physik, 55099 Mainz, Germany
2 GSI, 64291 Darmstadt, Germany
3 Stahl-Electronics, 67582 Mettenheim, Germany
4 Imperial College London, U.K.
The g-factor of the bound electron serves as sensitive test for bound-state quantum
electrodynamics (BS-QED) calculations. High precision experiments using single ions in a
double-Penning trap have been carried out in the past on hydrogen-like C 5+ [1] and O 7+ [2].
Based on the experience with these systems we plan similar experiments on hydrogenic ions
with higher nuclear charge Z. At present we work on Ca 19+ [3]. Since the BS-QED effects
scale approximately with Z 2 this should allow higher sensitivity.
Using novel detection techniques for observing induced spin flip transitions on a single
particle [4] we are setting up a Penning trap experiment to measure the g-factor of the proton
with high precision [5]. A similar experiment is planned for the future on the anti-proton. A
comparison of the g-factors of both particles will represent a test of the CPT invariance.
References
[1] H.Haeffner et al., Phys. Rev. Lett. 85, 5308 (2000)
[2] J. Verdu et al., Phys .Rev. Lett. 92, 093002 (2004)
[3] B. Schabinger et al., J. Phys.: Conf. Series 58, 121 (2007) (Proc. HCI 2006, Belfast )
[4] S. Stahl et al., J. Phys. B 38, 297 (2005)
[5] J. Verdú et al., AIP Conf. Proc. 796, 260 (2005) (Proc. LEAP-05)

A single Ca + ion for optical frequency metrology
C. Zumsteg, C. Champenois, G. Hagel, M. Houssin, D. Guyomarc’h, F. Vedel, M. Knoop
PIIM, Université de Provence-CNRS, Centre de Saint Jérôme, case C21,
13397 Marseille cedex 20, France.
Rf trapped earth-alkaline ions are versatile candidates for frequency metrology. Among
the candidates for an optical frequency standard, a single Ca+ ion is extremely attractive.
The electric quadrupole transition at 729 nm proposed as frequency reference (clock transition)
has a natural linewidth below 200 mHz corresponding to a quality factor of 2.10 15 ; the
wavelengths of the required lasers lie in the visible and near-infrared domain.
The ion is stored in a miniature radiofrequency trap, allowing interrogation times
beyond an hour, and giving access to the Lamb-Dicke regime. Probing of the clock transition
in a single ion is carried out using the quantum jump statistics as a function of the clock
laser frequency. The integration time needed to record an excitation spectrum may reach a
couple of seconds. The probing laser must therefore have an outstanding frequency stability
on this time scale with a line width at the hertz level.
Our local oscillator is a lab-built titanium-sapphire laser pumped with 5 W of laser
radiation at 532 nm (Coherent Verdi V5). The pre-stabilisation stage consists of a Pound-
Drever-Hall (PDH) lock onto a 30-cm Invar cavity. The cavity, which has a finesse of about
1000, is isolated from external perturbations with a vacuum chamber. Measurement by an
auto-correlation technique yields a linewidth below a few kHz with a resolution limited by
the length of our optical fibre (10 km).
Absolute frequency stabilisation of the clock laser on a
high-finesse (F =100000) ULE cavity of 150mm length
is under construction. In order to improve the stability
of the clock laser, we have chosen a tapered geometry
vertically supported near its midplane [1](see figure).
Elastic deformation of the cavity has been analysed using
a finite elements method to optimize the supporting
surface. Improving the stability of the cavity length requires
also the reduction of thermal fluctuations. Passive
and active isolation stages, composed respectively
by three thermal shields and by an active temperature
stabilisation on the vacuum chamber, are under construction.
Recent advancement regarding the realisation
of the cavity and the clock laser, will be presented.
[1] Lisheng Chen, John L. Hall, Jun Ye, Tao Yang, Erjun
Zang, and Tianchu Li. Vibration-induced elastic
deformation of Fabry-Perot cavities. Phys. Rev A,
74:053801, 2006.
Vertical ULE cavity of 150mm length

Search for Time-Variation of the Electron-Proton Mass Ratio with MilliKelvin
Trapped Molecular Ions
Brian Odom,
Kavli Institute for Cosmological Physics
University of Chicago
Abstract:
Most extensions of the standard model predict that if the fundamental constants vary with
time, the electron-proton mass ratio should change 30-40 times more rapidly than the fine
structure constant. However, in current model-independent laboratory searches, sensitivity to
time-dependence of the electron-proton mass ratio lags behind that of the fine structure
constant by two orders of magnitude. I present a proposal to improve sensitvity to timevariation
of the electron-proton mass ratio using spectroscopy on milliKelvin trapped
molecular ions. Specifically, the molecular ions of interest have a long-lived electronic state
nearly degenerate with a highly-excited vibrational level of the electronic ground state.

MOLECULES AND INTERACTIONS

Structural characterization of the protonated,
phosphorylated dipeptide [Gly-pTyrH] + in the gas phase
Catarina F. Correia a , Undine Erlekam b , Philippe Maître b and Gilles
Ohanessian a
a Laboratoire des Mécanismes Réactionels, Département de Chimie, Ecole
Polytechnique, CNRS, 91128, Palaiseau Cedex, France
b Laboratoire de Chimie Physique, Université Paris Sud 11, CNRS, 91405
Orsay Cedex, France
Phosphorylation of alcoholic side chains is one of the most frequent posttranslational
modifications (PTM) of proteins. It is known that the functionality
of a protein changes with the degree of phosphorylation, which can
most probably be referred to the conformational changes that are involved.
In order to understand the reactivity/functionality of a phosphorylated protein,
it is therefore imperative to explore its structural properties and to
locate the phosphorylated side chain(s). Infrared Multi Photon Dissociation
(IRMPD) spectroscopy, in combination with density functional theory
(DFT) calculations, has been proven to be a suitable tool to distinguish between
phosphorylated and non-phosphorylated residues in the protonated
amino acids serine, threonine and tyrosine [1]. The results on the isolated
amino acids allow for a bottom-up approach to characterize small phosphorylated
peptides in the gas phase.
Here, we present a combined experimental (IRMPD) and theoretical (DFT)
study of the protonated dipeptide [Gly-pTyrH] + which can serve as a model
system to explore the impact of a phosphorylated side chain on the structure
of a small peptide. IRMPD spectroscopy is performed using tunable IR
light from a free electron laser (FEL) and a Fourier transform ion cyclotron
resonance (FT-ICR) mass spectrometer. The characteristic phosphate vibrations
can be found in the energy range between 1000 and 1400 cm −1 .
Interestingly, the spectrum of [Gly-pTyrH] + in this energy range differs significantly
from that of the protonated amino acid [pTyrH] + . Comparison to
calculated spectra shows that the experimental spectrum results from two
different conformers.
Currently the secondary structure of peptides is probed using the amide
I and II bands. The spectral range above 1000 cm −1 is, however, often
congested by other vibrational modes and combination bands. For an unambiguous
structural assignment it is therefore desirable to find structural
probes at lower energies. A setup is presented that allows one to trap and
vibrationally cool molecular ions, to form weakly bound complexes and to
investigate their vibrational modes below 1000 cm −1 .
[1] C. F. Correia, P. O. Balaj, D. Scuderi, P. Maître, G. Ohanessian, J. Am. Chem. Soc.
130, 3359 (2008).

A tandem mass spectrometer for photodissociation spectroscopy of cold
biomolecular ions in the gas phase
U. J. Lorenz, A. Svendsen, O. V. Boyarkin and T. R. Rizzo
Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
Within recent years, spectroscopic studies of biomolecular ions in the gas phase have attracted
increased interest since they allow for the systematic investigation of the intrinsic properties of
biomolecules as well as their interactions with the solvent. They can thus be used to test quantum
chemical calculations and to establish an understanding of biological systems at a molecular
level. Ultraviolet (UV) and infrared (IR) spectroscopy have successfully been applied to this task,
yet face the problem that with larger systems spectral congestion limits the amount of information
that can be extracted.
Our group has recently addressed this issue in studies on protonated aminoacids. The
experimental setup comprises a tandem quadrupole mass spectrometer featuring a liquid helium
cooled 22-pole ion trap in which the ions are cooled to 10 K. Spectral congestion due to thermal
broadening can thus be considerably reduced [1]. Furthermore, by employing an IR/UV double
resonance scheme conformation specific spectra can be obtained. Thus, congestion due to
conformational heterogeneity can be eliminated.
Here we present a second generation apparatus, schematically depicted below, which is currently
under construction in our lab. The principle of operation will be as follows: Ions are produced by
nano electrospray and enter into the vacuum region via a heated capillary. A Smith-type ion
funnel [2] is used to transfer the ions efficiently to a hexapole ion trap from where ion packets are
released periodically. After mass selection in a quadrupole mass filter they pass an octopole ion
guide and are trapped in the 4 K cold 22-pole ion trap where they are cooled in collisions with
helium. Subsequently, the ions are irradiated with a UV (IR) laser and released from the trap.
Parent and fragment ions are then analyzed by means of a second quadrupole mass filter.
A FAIMS stage (field asymmetric waveform ion mobility spectrometry) can be inserted between
the needle and the transfer capillary which will allow for enhanced conformer selection [3].
Furthermore, an orthogonal time of flight (TOF) mass spectrometer will be added after the 22-
pole ion trap which will enable us to obtain the entire mass spectrum of the ion packet in a single
machine cycle. We will explore possibilities to compress the ion packet that leaves the cold trap
in the extraction region of the TOF MS in order to increase sensitivity.
[1] O. V. Boyarkin, S. R. Mercier, A. Kamariotis, and T. R. Rizzo, J. Am. Chem. Soc. 2006, 128,
2816.
[2] J. S. Page, K. Tang, and R. D. Smith, Int. J. of Mass Spect. 2007, 265, 244.
[3] R. W. Purves, R. Guevremont, S. Day, C. W. Pipich, and M. S. Matyjaszczyk, Rev. Sci.
Instrum. 1998, 69, 4094.

Collinear laser spectroscopy with cooled and trapped radioisotopes at ISOLDE
E. Mané 1 , J. Billowes 1 , K. Blaum 2 , P. Campbell 1 , B. Cheal 1 , D. Forest 3 , K. Flanagan 4 , G. Neyens 4 , R. Neugart 5 , G.
Tungate 3 , P. Vingerhoets 4 , D. Yordanov 5 and The ISOLDE Collaboration 6
1
Schuster Laboratory, The University of Manchester, UK
2
GSI, Germany
3
School of Physics and Astronomy, The University of Birmingham, UK
4
IKS, KU Leuven, Belgium
5
University of Mainz, Germany
6
CERN, Switzerland
Collinear laser spectroscopy is a fast, Doppler­free technique for determining nuclear
observables such as magnetic dipole moments, electric quadrupole moments, spins and changes in
the mean­square charge radii. These information are extracted from the fluorescence detection of
resonant photons along the hyperfine spectra of atomic transitions.
The European Organization for Nuclear Research, CERN, hosts the world's premier isotope
separator on­line facility, ISOLDE. This facility has gone through several upgrades, one of which is
the recent installation of a gas­filled linear Paul trap after the high resolution separator sector. As
well as providing beams with reduced transverse emittance and energy spread, this device is also
able to accumulate the ions and release the sample in bunches with a definite time structure. This
upgrade allowed collinear laser spectroscopy to be performed on cooled and bunched ions at
ISOLDE for the first time.
As an example, radioactive potassium and stable rubidium beams were delivered for study with a
collinear laser spectroscopy setup. The cooling effect caused a 10­fold reduction of the beam
emittance with a longitudinal energy spread of less than 1eV for beams extracted at 30keV. The ion
beam and laser were focussed and overlapped through a 1mm alignment aperture. The narrow ion
beam required considerably less laser power, which reduced the background due to scattered light.
By tuning the beam cooler to accumulate and release the ions in bunches of 10μs, and setting the
detection system to record events during this time window, the signal­to­noise ratio was reduced by
a factor of 10 4 .
This improvent has opened new prospects for optical measurements of radioisotopes located further
from stability than has previously been possible at ISOLDE using high resolution collinear
techniques.

Towards sympathetic cooling of charged proteins
David Offenberg, Chaobo Zhang, Bernhard Roth, and Stephan Schiller
Institut für Experimentalphysik, Heinrich-Heine-Universität Düsseldorf, Germany
In our ion trap apparatus we can reliably produce ensembles of translationally cold
polyatomic molecular ions, e. g. for high-resolution spectroscopic studies, interactions with
radiation or neutral gases, or various other applications. The molecular ions are transferred to
the gas phase using an electro-spray ionization source (ESI). Via an octopole ion guide the
ions are guided to a linear radio frequency trap where they are sympathetically cooled by their
mutual interaction with laser-cooled 138 Ba + ions. So far, singly-protonated AlexaFluor350
ions (mass 411 amu) have been sympathetically cooled to less than 140 mK [1] and singlyprotonated
glycyrrhetinic acid ions (mass 471 amu) even further to less than 80 mK. Our
observations are well described by molecular dynamics simulations, which are used to
determine the number of ions, their spatial distribution, and translational temperatures [2].
Recently we could demonstrate the full potential of our apparatus by cooling highly charged
proteins. First evaluations show, that in one example an ensemble of 160 laser-cooled 138 Ba +
ions cooled 50 seventeenfold protonated cytochrome c ions (mass ~ 12400 amu) to less than
1 K. To our knowledge this is by far the heaviest molecular ion sympathetically cooled up to
now.
[1]
A. Ostendorf, C. B. Zhang, M. A. Wilson, D. Offenberg, B. Roth, and S. Schiller,
Sympathetic Cooling of Complex Molecular Ions to Millikelvin Temperatures, Phys. Rev.
Lett. 97, 243005 (2006) + Erratum, Phys. Rev. Lett. 100, 019904 (2008)
[2]
C. B. Zhang, D. Offenberg, B. Roth, M. A. Wilson, and S. Schiller, Molecular-dynamics
simulations of cold single-species and multispecies ion ensembles in a linear Paul trap,
Phys. Rev. A 76, 012719 (2007)

Cold Chemistry with Cold Ions
Stefan Willitsch 1,2 , Martin T. Bell 2 , Alexander D. Gingell 2 , James M. Oldham 2 and
Timothy P. Softley 2
1 Department of Chemistry, University College London, London WC1H 0AJ, UK
2 Department of Chemistry, University of Oxford, Oxford OX1 3TA, UK
The recent development of a range of techniques for producing “cold” molecules at
very low translational temperatures T≤1 K in the gas phase has provided the
opportunity for studying collisional processes in a new physical regime. A new
experimental method to study reactive collisions between ions and neutral molecules
at very low temperatures will be presented which allows for tunable collision energies
and a variety of chemically diverse reaction partners 1 . Our technique relies on the
combination of a quadrupole-guide velocity selector for the generation of cold neutral
molecules with a facility to produce strongly ordered samples of laser-cooled ions in
an ion trap usually referred to as Coulomb crystals. Because of the strong localization
of the ions chemical reactions can be studied with single-particle sensitivity. Our new
technique represents a general approach to study reactive collisions between ions and
polar neutral molecules over a wide temperature range down to the cold regime and is
particularly suited to investigate chemical reactions of astrophysical relevance at the
low temperatures prevalent in the interstellar medium. We will report results on a
proof-of-principle experiment on the chemical reaction between translationally cold
CH 3 F molecules and laser-cooled Ca + ions to form CaF + and CH 3 which was studied
in a collision energy range corresponding to 1-10 K. The characteristics of our coldmolecule
sources and the performance of the new technique as well as perspectives
for further developments will be discussed.
1 S. Willitsch, M.T. Bell, A. D. Gingell, S. R. Procter and T. P. Softley, Phys. Rev. Lett. 100 (2008), 043203

Isotope selective trapping with linear Paul traps
Shuichi Hasegawa
School of Engineering, The University of Tokyo, Japan
hasegawa@q.t.u-tokyo.ac.jp
Linear Paul traps have good mass selectivity and can confine ions in a fixed
space. Recent progress in quantum electronics, especially laser cooling
techniques, led atoms and ions to low temperatures. Laser cooling of trapped
ions allows the non-destructive observation of single ions through their laser
induced fluorescence (LIF). The laser cooling also reduces the Doppler
broadened linewidth, which enables one to resolve the isotope shifts of the ions.
Therefore, we have proposed the application of the ion trapping and laser
cooling techniques to the measurement of isotope ratios and trace isotope
analysis [1]. In order to maximize the sensitivity, one needs to efficiently trap the
isotope of interest. In this report, we show isotope selectivity of trapped ions with
a linear Paul trap and observation of their LIFs using the laser cooling technique.
Calcium ions are generated by pulsed Nd:YAG laser ablation. Slow ions can be
trapped in the linear Paul trap. This method generates ions easily and a large
number of ions can be loaded [2]. After cooling the trapped ions, we can observe
the calcium isotopes. In order to purify the trapped isotopes, we scan the rf
amplitude and static voltage applied to the electrodes, which correspond to q
and a parameters of the Mathieu equations. Lighter mass isotopes ( 40, 42 Ca + )
are repelled by the initial rf voltage conditions. By applying +8V to the electrode
(U dc ), 48 Ca + are expelled from the trap and only 44 Ca + ions remain in it.
We demonstrated the isotope selectivity of trapped ions by changing the
voltages applied to the electrodes of the linear Paul trap. The results were
confirmed by observing the laser induced fluorescence enhanced by the laser
cooling method. This method can be utilized to efficiently accumulate a large
number of rare isotopes and measure the isotope ratios.
Acknowledgements: The author acknowledges the productive work of his colleagues,
Y. Hashimoto, D. Nagamoto.
References: [1] S. Hasegawa, et al. J. Nucl. Sci. Technol. 43, 300 (2006). [2] Y.
Hashimoto, et al., Jpn. J. Appl. Phys. 45, 7108 (2006).

AN ION TRAP FOR LASER SPECTROSCOPY OF COLD HIGHLY-CHARGED IONS
R.C. Thompson 1 , D.M. Segal 1 , S. Bharadia 1
W. Nörtershäuser 2,3 , D.F.A. Winters 2 , M. Vogel 1,2 , Z. Andjelkovic 1,2
and the SPECTRAP collaboration
1 Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, UK
2
GSI mbH, Atomphysik, Planckstrasse 1, D-64291 Darmstadt, Germany
3
Uni Mainz, Institut für Kernchemie, Fritz-Strassmann-Weg 2, D-55099 Mainz, Germany
We present an overview of SPECTRAP, an experiment under construction at GSI, which will
perform high-precision laser spectroscopy measurements of the ground-state hyperfine splitting
(HFS) of cold highly-charged ions (HCI), as a direct test of bound state QED at high fields. The
experiment is situated in the new ion trap facility of HITRAP [1], which will be operational in late
2008, and will be able to deliver approximately 10 5 cold (4K), bunched HCI to several Atomic
Physics experiments [2].
The ion trap, a cylindrical Penning trap, has been constructed and tested as a radio frequency trap.
The experimental setup uses the RETRAP [3] cold-bore superconducting magnet. HCI from the
HITRAP Cooler Trap will be captured in flight, resistively cooled and compressed using a rotating
dipole field [4]. In resistive cooling, energy is lost from the ion motion via currents induced in an
external cryogenically-cooled resistor within a resonant circuit. Cooling is required to reduce
Doppler broadening of the (M1) transitions of interest and cloud compression is necessary to
maximise the fluorescence from the ions. Laser spectroscopy will be performed with an on-axis
laser beam that excites the hyperfine transition within the ion’s ground-state.
We aim to measure the HFS with a relative precision of 10 −7 . By comparison of both H-like and
Li-like ions of the same isotope, QED effects can be extracted, at the strongest electromagnetic
fields available, on the level of a few percent [5].
Currently at GSI, we are working on bringing the magnet online, which will be used with a local
EBIT for early tests with heavy ions. At Imperial, due the availability of our own superconducting
magnet, an identical ion trap will shortly be run in a Penning configuration with low charge light
ions. This will allow us to test both the trap optics and the rotating wall drive.
[1] T. Beier, et al,, Nucl. Instr. Meth. Phys. Res. B 235, 473 (2005)
[2] "HITRAP: A facility at GSI for highly charged ions" H.-J. Kluge, et al, Advances in Quantum
Chemistry 53 (2007) 83.
[3] Lukas Gruber, et al, Phys. Scr. 71, 60-107 (2005)
[4] D.F.A. Winters, A.M. Abdulla, J.R. Castrejón Pita, A. de Lange, D.M. Segal and
R.C. Thompson, Nucl. Instr. Meth. Phys. Res. B 235, 201 (2005)
[5] D.F.A. Winters, M. Vogel, D.M. Segal, R.C. Thompson and W. Nörtershäuser, Can. J. Phys
85, 403-408 (2007)