2018/07/24 by Sangita Bera, Rhombik Roy, Bera, S. +7
Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #FOS: Physical sciences #Physics of Superconductivity and Magnetism #Quantum Gases (cond-mat.quant-gas) #Quantum, superfluid, helium dynamics
paper · doi:10.48550/arxiv.1807.09003
openalex publication_date 2018/07/24 · openalex created_date 2018/08/03 · openalex updated_date 2026/07/28
Understanding the relaxation process is the most important unsolved problem in non-equilibrium quantum physics. Current understanding primarily concerns on if and how an isolated quantum many-body system thermalize. However, there is no clear understanding of what conditions and on which time-scale do thermalization occurs. In this article, we simulate the quench dynamics of one-dimensional Bose gas in an optical lattice from an\it ab initio perspective by solving the time-dependent many-boson Schrödinger equation using the multi-configurational time-dependent Hartree method for bosons (MCTDHB). We direct a superfluid (SF) to Mott-insulator (MI) transition by performing two independent quenches: an interaction quench when the interaction strength is changed instantaneously, and a lattice depth quench where the depth of the lattice is altered suddenly. We show that although the Bose-Hubbard model predicts identical physics, the general many-body treatment shows significant differences between the two cases. We observe that lattice depth quench exhibits a large time-scale to reach the MI state and shows an oscillatory phase collapse-revival dynamics and a complete absence of thermalization that reveals through the analysis of the time-evolution of the reduced one-body density matrix, two-body density, and entropy production. In contrast, the interaction quench shows a swift transition to the MI state and shows a clear signature of thermalization for strong quench values. We provide a physical explanation for these differences and prescribe an analytical fitting formula for the time required for thermalization.