We demonstrate a reinforcement learning(RL)-based control framework for optimizing evaporative cooling in the preparation of strongly interacting degenerate Fermi gases of 6Li.Using a Soft Actor-Critic(SAC)algorithm,t...We demonstrate a reinforcement learning(RL)-based control framework for optimizing evaporative cooling in the preparation of strongly interacting degenerate Fermi gases of 6Li.Using a Soft Actor-Critic(SAC)algorithm,the system autonomously explores a high-dimensional parameter space to learn optimal cooling trajectories.Compared to conventional exponential ramps,our method achieves up to 130%improvement in atomic density within 0.5 second,revealing non-trivial control strategies that balance fast evaporation and thermalization.While our current optimization focuses on the evaporation stage,future integration of other cooling stages,such as gray molasses cooling,could further extend RL to the full preparation pipeline.Our result highlights the promise of RL as a general tool for closed-loop quantum control and automated calibration in complex atomic physics experiments.展开更多
We study the expansion behaviors of a Fermionic superfluid in a cigar-shaped optical dipole trap for the whole BEC-BCS crossover and various temperatures.At low temperature(0.06(1)T_(F)),the atom cloud undergoes an an...We study the expansion behaviors of a Fermionic superfluid in a cigar-shaped optical dipole trap for the whole BEC-BCS crossover and various temperatures.At low temperature(0.06(1)T_(F)),the atom cloud undergoes an anisotropic hydrodynamic expansion over 30 ms,which behaves like oscillation in the horizontal plane.By analyzing the expansion dynamics according to the superfluid hydrodynamic equation,the effective polytropic index y of Equation-of-State(EoS)of Fermionic superfluid is extracted.The y values show a non-monotonic behavior over the BEC-BCS crossover,and have a good agreement with the theoretical results in the unitarity and BEC side.The normalized quasi-frequencies of the oscillatory expansion are measured,which drop significantly from the BEC side to the BCS side and reach a minimum value of 1.73 around 1/k_(F)a=-0.25.Our work improves the understanding of the dynamic properties of strongly interacting Fermi gas.展开更多
基金supported by the Innovation Program for Quantum Science and Technology of China(Grant No.2024ZD0300100)the National Basic Research Program of China(Grant No.2021YFA1400900)+1 种基金Shanghai Municipal Science and Technology(Grant Nos.25TQ003,2019SHZDZX01,and 24DP2600100)the National Natural Science Foundation of China(Grant No.12304555).
文摘We demonstrate a reinforcement learning(RL)-based control framework for optimizing evaporative cooling in the preparation of strongly interacting degenerate Fermi gases of 6Li.Using a Soft Actor-Critic(SAC)algorithm,the system autonomously explores a high-dimensional parameter space to learn optimal cooling trajectories.Compared to conventional exponential ramps,our method achieves up to 130%improvement in atomic density within 0.5 second,revealing non-trivial control strategies that balance fast evaporation and thermalization.While our current optimization focuses on the evaporation stage,future integration of other cooling stages,such as gray molasses cooling,could further extend RL to the full preparation pipeline.Our result highlights the promise of RL as a general tool for closed-loop quantum control and automated calibration in complex atomic physics experiments.
基金supported by the National Natural Science Foundation of China (11874340)the National Key R&D Program of China (2018YFA0306501)+2 种基金the CASthe Anhui Initiative in Quantum Information Technologiesthe Fundamental Research Funds for the Central Universities (WK2340000081)
文摘We study the expansion behaviors of a Fermionic superfluid in a cigar-shaped optical dipole trap for the whole BEC-BCS crossover and various temperatures.At low temperature(0.06(1)T_(F)),the atom cloud undergoes an anisotropic hydrodynamic expansion over 30 ms,which behaves like oscillation in the horizontal plane.By analyzing the expansion dynamics according to the superfluid hydrodynamic equation,the effective polytropic index y of Equation-of-State(EoS)of Fermionic superfluid is extracted.The y values show a non-monotonic behavior over the BEC-BCS crossover,and have a good agreement with the theoretical results in the unitarity and BEC side.The normalized quasi-frequencies of the oscillatory expansion are measured,which drop significantly from the BEC side to the BCS side and reach a minimum value of 1.73 around 1/k_(F)a=-0.25.Our work improves the understanding of the dynamic properties of strongly interacting Fermi gas.
