Workshop book - Physikzentrum der RWTH Aachen - RWTH Aachen ...

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Posters Tuesday February 5 Poster 21: Optical Josephson radiation from a Majorana Josephson junction Christoph Ohm We consider a voltage-biased Josephson junction between two nanowires hosting Majorana fermions which occur as topological protected zero-energy excitations at the junction. We show that two Majorana fermions localized at the junction, though being neutral excitations, interact with the electromagnetic field and generate coherent radiation similar to the conventional Josephson radiation in a voltage biased Josephson junction. Within a semiclassical analysis of the light field, we find that the optical phase gets locked to the superconducting phase difference and that the radiation is emitted at half of the Josephson frequency. In order to confirm the coherence of the radiation, we study correlations of the light emitted by two spatiallyseparated junctions in a SQUID geometry taking into account decoherence by spontaneous phase-switchings due to quasi-particle poisoning as well as by thermal effects. Poster 22: Spin-flip excitations induced by time-dependent electric fields in surfaces with strong spin-orbit interaction Julen Ibanez Heavy element surfaces have become an ideal testing ground for investigating the nature and effects of the relativistic spin-orbit interaction in low dimensional systems. In this work, we study spin-flip transitions between the metallic surface states of the Pb/Ge(111) and the Rashba prototype Au(111) surfaces. We calculate the spin-flip matrix elements following an approach based on the interpolation of maximally localized Wannier functions. The obtained results show that spin-flip absorptions are one order of magnitude larger in Pb/Ge(111) than in Au(111), reaching a remarkable maximum of 6% absorption of the total irradiated light. We find that the enhanced spin-flip contribution in Pb/Ge(111) is closely connected to the behavior of the momentum dependent spin-polarization associated to the surface states. 72
Posters Tuesday February 5 Poster 23: Quantum Dots and Majorana Fermions Martin Leijnse Majorana fermions, particles which are their own anti-particles, may or may not exist as elementary particles in nature. However, it was shown theoretically a few years ago that they can appear as quasiparticle excitations in certain condensed matter systems combining superconductivity, magnetism, and strong spin-orbit coupling. This has quickly become one of the hottest topics in mesoscopic physics research, partly because of the possibility to use Majorana fermions for quantum information processing. I will present work suggesting a new and perhaps easier way to generate Majorana-like bound states in a double quantum dot system, where the dots are tunnel coupled to each other via a superconductor. I will also show that quantum dots can be used to do more accurate spectroscopy of Majorana systems, and even to manipulate quantum information stored in Majoranabased qubits. Poster 24: Disorder-induced topological phase transitions in a quasi-1D spinless p-wave superconductor Maria-Theresa Rieder Topological phases and the surface states associated with them are known to be robust against weak disorder and to break down at a critical disorder strength. In this letter we show how disorder induces a series of topological phase transitions in a spinless multichannel p-wave superconducting wire. We find that the wire alternates between topologically trivial and nontrivial phases as the induced superconductivity is increased in a perturbative approach to the transverse coupling. 73
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PROGRAM BOOK International workshop
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What comes with this booklet With t
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Getting to the institute (1) If you
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Workshop lecture hall • The works
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Lunch information Lunch will be tak
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Talks Monday February 4 Talk progra
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Talks Monday February 4 Notes 13
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Page 21 and 22: Talks Monday February 4 Notes 21
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Page 86 and 87: 18. Domenico Giuliano, Universita
Page 88 and 89: 55. Jens Paaske, Copenhagen Univers
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Workshop book - Physikzentrum der RWTH Aachen - RWTH Aachen ...

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