Universal Scaling Laws in the Dynamics of a Homogeneous Unitary Bose Gas

Abstract

We study the dynamics of an initially degenerate homogeneous Bose gas after an interaction quench to the unitary regime at a magnetic Feshbach resonance. As the cloud decays and heats, it exhibits a crossover from degenerate- to thermal-gas behaviour, both of which are characterised by universal scaling laws linking the particle-loss rate to the total atom number $N$. In the degenerate and thermal regimes the per-particle loss rate is $\propto N^{2/3}$ and $N^{26/9}$, respectively. The crossover occurs at a universal kinetic energy per particle and at a universal time after the quench, in units of energy and time set by the gas density. By slowly sweeping the magnetic field away from the resonance and creating a mixture of atoms and molecules, we also map out the dynamics of correlations in the unitary gas, which display a universal temporal scaling with the gas density, and reach a steady state while the gas is still degenerate.

5 pages, 5 figures

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• Efimov Physics in Cold Atoms
• Two-dimensional dynamics of expansion of a degenerate Bose gas
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• Strongly correlated Bose gases
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Cited by in corpus (5)

• Anomalous frequency shifts in a one-dimensional trapped Bose gas
• Bunching, clustering, and the buildup of few-body correlations in a quenched unitary Bose gas
• Pair formation in quenched unitary Bose gases
• High Temperature Virial Expansion to Universal Quench Dynamics
• Two-Step Production of Resonant Bose-Einstein Condensates