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Cooling an Optically Trapped Ultracold Fermi Gas by Periodical Driving
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Anomalous Breaking of Scale Invariance in a Two-Dimensional Fermi Gas.
M Holten1, L Bayha1, A C Klein1
1Physikalisches Institut, Ruprecht-Karls-Universität Heidelberg, 69120 Heidelberg, Germany.
Physical Review Letters
|October 9, 2018
Summary
We studied the breathing mode frequency shifts in a two-dimensional Fermi gas. Scale invariance breaking leads to anomalous shifts, dependent on interaction strength in ultracold atoms.
Area of Science:
- Quantum physics
- Ultracold atomic gases
- Condensed matter physics
Background:
- The breathing mode frequency of a 2D Fermi gas is typically set by scale invariance.
- Quantum anomalies can break scale invariance, affecting collective modes.
- Previous work identified scale invariance breaking via scattering length in quantized theories.
Purpose of the Study:
- Investigate the anomalous frequency shift of the collective breathing mode in a two-component Fermi gas.
- Explore this phenomenon in the strongly interacting regime.
- Quantify the interaction dependence of the observed frequency shifts.
Main Methods:
- Utilizing ultracold atom experiments.
- Confining a two-component Fermi gas in a harmonic trap.
- Measuring the frequency of the collective breathing mode.
- Tuning the interaction strength via the scattering length.
Main Results:
- Observed significant upward shifts in the breathing mode frequency.
- Demonstrated a strong dependence of these shifts on interaction strength.
- Confirmed deviations from the scale-invariant prediction.
Conclusions:
- Scale invariance is anomalously broken in strongly interacting 2D Fermi gases.
- The observed frequency shifts provide evidence for quantum anomalies in ultracold atomic systems.
- Interaction strength is a critical factor in the anomalous behavior of collective modes.
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