准凝聚体中暗孤子的涨落和耗散动力学
Fluctuating and dissipative dynamics of dark solitons in quasi-condensates
摘要：
用数值和解析方法研究了部分凝聚玻色气体中物质波暗孤子的涨落和耗散动力学。对随机Gross-Pitaevskii方程的研究（该方程正确地解释了有限温度下的密度和相位波动）揭示了暗孤子衰减时间在每个温度下是对数正态分布的，从而表征了先前预测的每个数值实现系综内的长寿命孤子轨迹（S. P. Cockburn { \it et al.}，物理修订信函104，174101（2010））。从这些分布中提取的平均孤子寿命的期望值被发现同意以及基于耗散Gross-Pitaevskii模型（具有相同的{ \it从头算}阻尼）的数值和分析预测。探索的制度，其中$0.8 k_{B}T < μ< 1.6 k_{B}T$，我们发现平均孤子寿命的规模与温度为$τ\sim T^{-4}$，与以前的预测为低温制度$k_{B}T\llμ$。该模型还示出捕获实验相关的减少由于背景波动的存在下，振荡孤子的可见性。
英文摘要：
The fluctuating and dissipative dynamics of matter-wave dark solitons within harmonically trapped, partially condensed Bose gases is studied both numerically and analytically. A study of the stochastic Gross-Pitaevskii equation, which correctly accounts for density and phase fluctuations at finite temperatures, reveals dark soliton decay times to be lognormally distributed at each temperature, thereby characterizing the previously predicted long lived soliton trajectories within each ensemble of numerical realizations (S.P. Cockburn {\it et al.}, Phys. Rev. Lett. 104, 174101 (2010)). Expectation values for the average soliton lifetimes extracted from these distributions are found to agree well with both numerical and analytic predictions based upon the dissipative Gross-Pitaevskii model (with the same {\it ab initio} damping). Probing the regime for which $0.8 k_{B}T < μ< 1.6 k_{B}T$, we find average soliton lifetimes to scale with temperature as $τ\sim T^{-4}$, in agreement with predictions previously made for the low-temperature regime $k_{B}T\llμ$. The model is also shown to capture the experimentally-relevant decrease in the visibility of an oscillating soliton due to the presence of background fluctuations.
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