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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8.7 Future Outlook<br />
With the current progress <strong>to</strong>wards generat<strong>in</strong>g a degenerate gas <strong>and</strong> the demon-<br />
strated ability <strong>to</strong> create a small dipole trap for laser cull<strong>in</strong>g, the experiment should be<br />
able <strong>to</strong> generate a<strong>to</strong>mic Fock states of lithium a<strong>to</strong>ms <strong>in</strong> the near future.<br />
Evaporation until degeneracy is reached is work <strong>in</strong> progress. To reduce the evap-<br />
oration time, evaporation will be done closer <strong>to</strong> the Feshbach resonance, <strong>in</strong> the 750 <strong>to</strong><br />
834 G range. However, close <strong>to</strong> resonance the scatter<strong>in</strong>g length is positive <strong>and</strong> molecules<br />
can be formed [30]. Evaporation <strong>to</strong> degeneracy will therefore be f<strong>in</strong>ished at 300 G, where<br />
the scatter<strong>in</strong>g length is negative.<br />
Once degeneracy is verified, the objective <strong>and</strong> the other optics shown <strong>in</strong> figure<br />
7.40 will be added <strong>to</strong> the experimental setup <strong>and</strong> lithium a<strong>to</strong>ms can be loaded from<br />
the CO2 optical dipole trap <strong>to</strong> the small YAG dipole trap <strong>to</strong> <strong>in</strong>itialize the laser cull<strong>in</strong>g<br />
sequence. How <strong>to</strong> best load this small dipole trap is still an open question. Especially<br />
the tim<strong>in</strong>g of the turn on <strong>and</strong> the turn on speed will have <strong>to</strong> be determ<strong>in</strong>ed, keep<strong>in</strong>g <strong>in</strong><br />
m<strong>in</strong>d that excitations especially <strong>to</strong> the lowest energy levels have <strong>to</strong> be avoided. With<br />
the right comb<strong>in</strong>ation of laser power, magnetic field gradient, offset magnetic field, <strong>and</strong><br />
cull<strong>in</strong>g time Fock states of a<strong>to</strong>ms can then be created.<br />
Hav<strong>in</strong>g achieved the miles<strong>to</strong>ne of Fock state production, many different exper-<br />
iments can be envisioned. The study of quantum entanglement on the s<strong>in</strong>gle particle<br />
level us<strong>in</strong>g neutral a<strong>to</strong>ms is one path <strong>to</strong> follow. Creat<strong>in</strong>g an entangled pair of a<strong>to</strong>ms <strong>in</strong><br />
the lithium system will <strong>in</strong>volve splitt<strong>in</strong>g the 2-a<strong>to</strong>m Fock state <strong>in</strong><strong>to</strong> two separate traps.<br />
This splitt<strong>in</strong>g can be done by ”pa<strong>in</strong>t<strong>in</strong>g” a time-averaged potential of the traps with the<br />
use of an AOM. Chang<strong>in</strong>g the driv<strong>in</strong>g frequency of the AOM on time scales faster than<br />
the trapp<strong>in</strong>g frequencies will avoid heat<strong>in</strong>g of the a<strong>to</strong>ms but <strong>in</strong>stead they will experience<br />
the time-averaged potential. It has been shown that this method is <strong>in</strong>deed applicable <strong>to</strong><br />
degenerate gases [120].<br />
The generation of scalable quantum entanglement is the ultimate goal of the<br />
lithium experiment. Once the production of a Fock state <strong>in</strong> a s<strong>in</strong>gle site <strong>and</strong> the splitt<strong>in</strong>g<br />
<strong>in</strong><strong>to</strong> separate wells are well unders<strong>to</strong>od, multiple sites can be implemented <strong>in</strong><strong>to</strong> the<br />
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