近日，新西兰奥塔哥大学的Nils A. Krause和Ashton S. Bradley合作并取得一项新进展。经过不懈努力，他们揭示了平面琼斯-罗伯茨孤子的热衰减特性。相关研究成果已于2024年11月4日在国际知名学术期刊《物理评论A》上发表。
在这项工作中，研究人员基于描述储层相互作用的随机投影Gross-Pitaevskii理论，发展了平面孤子因热效应而衰减的理论。研究人员分析了涉及凝聚体与非凝聚体储层之间转移的两种不同阻尼项：一种是同时涉及能量转移并通常驱动凝聚体增长的粒子转移，另一种是保持粒子数守恒的能量转移。研究人员对低速和高速区域都进行了理论分析，并确定了每种机制占主导的条件。
这项研究结果表明，在高相空间密度下，能量阻尼占主导地位。这些理论结果得到了覆盖从涡旋偶极子到稀疏脉冲整个速度范围的数值研究的支持。研究人员使用相互作用能来表征稀疏脉冲，类似于涡旋偶极子中涡旋之间的距离，这为玻色-爱因斯坦凝聚体中的有限温度理论提供了一个实验上可验证的测试方法。
据悉，均质平面超流体表现出一系列低能激发态，这些激发态同样也会出现在如超流体湍流等高激发态中。在稀薄气体玻色-爱因斯坦凝聚体中，琼斯-罗伯茨孤子族在低速和高速区域分别包含涡旋偶极子和稀疏脉冲。这些激发态既携带能量也携带线性动量，因此它们的衰减特性对于理解超流体动力学至关重要。
附：英文原文
Title: Thermal decay of planar Jones-Roberts solitons
Author: Nils A. Krause, Ashton S. Bradley
Issue&Volume: 2024/11/04
Abstract: Homogeneous planar superfluids exhibit a range of low-energy excitations that also appear in highly excited states like superfluid turbulence. In dilute gas Bose-Einstein condensates, the Jones-Roberts soliton family includes vortex dipoles and rarefaction pulses in the low- and high-velocity regimes, respectively. These excitations carry both energy and linear momentum, making their decay characteristics crucial for understanding superfluid dynamics. In this work, we develop the theory of planar soliton decay due to thermal effects, as described by the stochastic projected Gross–Pitaevskii theory of reservoir interactions. We analyze two distinct damping terms involving transfer between the condensate and the noncondensate reservoir: particle transfer that also involves energy and usually drives condensate growth, and number-conserving energy transfer. We provide analytical treatments for both the low- and high-velocity regimes and identify conditions under which either mechanism dominates. Our findings indicate that energy damping prevails at high phase-space density. These theoretical results are supported by numerical studies covering the entire velocity range from vortex dipole to rarefaction pulse. We use interaction energy to characterize rarefaction pulses, analogous to the distance between vortices in vortex dipoles, offering an experimentally accessible test for finite-temperature theory in Bose-Einstein condensates.
DOI: 10.1103/PhysRevA.110.053302
Source: https://journals.aps.org/pra/abstract/10.1103/PhysRevA.110.053302
来源：科学网 小柯机器人