Experiments to Control Atom Number and Phase-Space Density in ...
Experiments to Control Atom Number and Phase-Space Density in ...
Experiments to Control Atom Number and Phase-Space Density in ...
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<strong>Experiments</strong> <strong>to</strong> <strong>Control</strong> A<strong>to</strong>m <strong>Number</strong> <strong>and</strong> <strong>Phase</strong>-<strong>Space</strong><br />
<strong>Density</strong> <strong>in</strong> Cold Gases<br />
Kirsten Vier<strong>in</strong>g, Ph.D.<br />
The University of Texas at Aust<strong>in</strong>, 2012<br />
Supervisor: Mark G. Raizen<br />
This dissertation presents the development <strong>and</strong> implementation of two novel ex-<br />
perimental techniques for controll<strong>in</strong>g a<strong>to</strong>m number <strong>and</strong> phase-space density <strong>in</strong> cold<br />
a<strong>to</strong>mic gases.<br />
The first experiment demonstrates the method of s<strong>in</strong>gle-pho<strong>to</strong>n cool<strong>in</strong>g, an optical<br />
realization of Maxwell’s demon, us<strong>in</strong>g an ensemble of rubidium a<strong>to</strong>ms. S<strong>in</strong>gle-pho<strong>to</strong>n<br />
cool<strong>in</strong>g <strong>in</strong>creases the phase-space density of a cloud of magnetically trapped a<strong>to</strong>ms,<br />
reduc<strong>in</strong>g the entropy of the ensemble by irreversibly transferr<strong>in</strong>g a<strong>to</strong>ms through a one-<br />
way wall via a s<strong>in</strong>gle-pho<strong>to</strong>n scatter<strong>in</strong>g event. While traditional laser cool<strong>in</strong>g methods are<br />
limited <strong>in</strong> their applicability <strong>to</strong> a small number of a<strong>to</strong>ms, s<strong>in</strong>gle-pho<strong>to</strong>n cool<strong>in</strong>g is much<br />
more general <strong>and</strong> should <strong>in</strong> pr<strong>in</strong>ciple be applicable <strong>to</strong> almost all a<strong>to</strong>ms <strong>in</strong> the periodic<br />
table. The experiment described <strong>in</strong> this dissertation demonstrates a one-dimensional<br />
implementation of the cool<strong>in</strong>g scheme. Complete phase-space compression along this<br />
dimension is observed. The limitations on the cool<strong>in</strong>g performance are shown <strong>to</strong> be<br />
given by trap dynamics <strong>in</strong> the magnetic trap.<br />
The second part of this dissertation is dedicated <strong>to</strong> the experiment built <strong>to</strong> con-<br />
trol the a<strong>to</strong>m number of a degenerate Fermi gas on a s<strong>in</strong>gle particle level. Creat<strong>in</strong>g Fock<br />
states of a<strong>to</strong>ms with ultra-high fidelity is a m<strong>and</strong>a<strong>to</strong>ry step for study<strong>in</strong>g quantum entan-<br />
glement on a s<strong>in</strong>gle a<strong>to</strong>m level. The experimental technique implemented <strong>to</strong> control the<br />
a<strong>to</strong>m number <strong>in</strong> this experiment is called laser cull<strong>in</strong>g. Decreas<strong>in</strong>g the trapp<strong>in</strong>g potential<br />
reduces the a<strong>to</strong>m number <strong>in</strong> a controlled way, giv<strong>in</strong>g precise control over the number<br />
of a<strong>to</strong>ms rema<strong>in</strong><strong>in</strong>g <strong>in</strong> the trap. This dissertation details the design <strong>and</strong> construction<br />
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