摘要
系统性地探讨了通过淬火相互作用在初态包含暗孤子的玻色-爱因斯坦凝聚体中产生量子冲击波的可能性及其内禀机制.在淬火至无相互作用极限下,解析得到了初始静止孤子的后续动力学,发现了冲击波的存在,并通过量子相干效应加以解释.在淬火至有限相互作用下,通过数值求解Gross-Piatevskii方程也发现了冲击波现象,并且分析了不同情形:往弱相互作用侧淬火时得到的冲击波与无相互作用情形类似;往强相互作用侧淬火时得到的冲击波伴随着孤子的劈裂,且两者存在同步变化关系.进一步探究了冲击波的特性,包括其振幅、速度,并得到了其随淬火相互作用强度变化的全景图谱.这一工作为实验上实现和观测冲击波提供了理论指导.
The Bose-Einstein condensate(BEC) formed by ultracold atomic gases provides an ideal platform for studying various quantum phenomena. In this platform, researchers have explored in depth the important equilibrium and steady phenomena including superfluidity, vortices, and solitons, and recently started to study nonequilibrium problems. In a classical system, nonequilibrium problems, such as explosion, usually occur together with shock waves, which is presented when the explosion speed is larger than the local sound speed.For BEC systems which possess quantum properties, how to produce and understand the shock waves becomes a hot research topic. In this work, we systematically discuss the possibility of quantum shock wave and its essential mechanism in a one-dimensional BEC initially containing dark solitons through quenching interactions.When the system is quenched to the limit of non-interaction, we analytically obtain the post-quench dynamics of initially immobile dark solitons, and find the existence of shock wave, which can be explained through the quantum interference effect. When the system is quenched to finite interaction, we find similar phenomena through numerically solving the Gross-Pitaevskii equation, and analyze different situations. When the system is quenched to a finite weaker interaction, the situation is similar to a non-interaction case;when the system is quenched to a stronger interaction, the shock wave is accompanied by the splitting of the initial soliton, and the two objects can synchronously change;specifically when the quenched ratio of strength is an integer squared,the shock wave disappears, and the soliton is split perfectly. We further explore the properties of the shock wave including its amplitude and speed, and obtain the full scenario as the quenched interaction varies. This work provides theoretical guidance for realizing and measuring shock wave in experiment.
作者
贾瑞煜
方乒乒
高超
林机
Jia Rui-Yu;Fang Ping-Ping;Gao Chao;Lin Ji(Department of Physics,Zhejiang Normal University,Jinhua 321004,China)
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2021年第18期17-24,共8页
Acta Physica Sinica
基金
国家自然科学基金(批准号:11835011,12074342)
浙江省基础公益研究计划(批准号:LY21A040004)资助的课题.
