首页|Universal dynamic scaling and Contact dynamics in quenched quantum gases

Universal dynamic scaling and Contact dynamics in quenched quantum gases

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Recently universal dynamic scaling is observed in several systems,which exhibit a spatiotemporal self-similar scaling behavior,analogous to the spatial scaling near phase transition.The latter one arises from the emer-gent continuous scaling symmetry.Motivated by this,we investigate the possible relation between the scaling dynamics and the continuous scaling symmetry in this paper.We derive a theorem that the scaling invariance of the quenched Hamiltonian and the initial density matrix can lead to the universal dynamic scaling.It is further demonstrated both in a two-body system analytically and in a many-body system numerically.For the latter one,we calculate the dynamics of quantum gases quenched from the zero interaction to a finite interaction via the non-equilibrium high-temperature virial expansion.A dynamic scaling of the momentum distribution appears in certain momentum-time windows at unitarity as well as in the weak interacting limit.Remarkably,this universal scaling dynamics persists approximately with smaller scaling exponents even if the scaling symmetry is fairly broken.Our findings may offer a new perspective to interpret the related experiments.We also study the Contact dynamics in the BEC-BCS crossover.Surprisingly,the half-way time displays a maxi-mum near unitarity while some damping oscillations occur on the BEC side due to the dimer state,which can be used to detect possible two-body bound states in experiments.

dynamic scalingContact dynamicsquantum gasescold atomquench dynamicsvirial expansioncontinuous scaling symmetry

Jia-Nan Cui、Zhengqiang Zhou、Mingyuan Sun

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School of Science,Beijing University of Posts and Telecommunications,Beijing 100876,China

State Key Lab of Information Photonics and Optical Communications,Beijing University of Posts and Telecommunications,Beijing 100876,China

国家自然科学基金Fund of State Key Laboratory of IPOC(BUPT)Fund of State Key Laboratory of IPOC(BUPT)

12004049600119525505019124

2024

物理学前沿
高等教育出版社

物理学前沿

CSTPCD
影响因子:0.816
ISSN:2095-0462
年,卷(期):2024.19(2)
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