【摘要】 我们利用解析和数值的方法,研究从Bardeen-Cooper-Schrieffer(BCS)超流到玻色-爱因斯坦凝聚(BEC)渡越的过程里超流费米气体中两维(2D)孤子的形成和演化.基于超流流体力学方程,在准二维和长波近似下,推导描述弱非线性激发带正色散项的Kadomtsev-Petviashvili方程;给出整个BCS-BEC渡越的2D孤子解,以及数值求解孤子在囚禁势中的演化.数值结果显示由于Snake(横向)不稳定性,大振幅的暗孤子会衰变为大量涡旋-反涡旋对,并且这个不稳定性在不同超流区域不同.更多还原

【Abstract】 We study,both analytically and numerically,the formation and dynamics of two- dimensional( 2D)solitons in the superfluid Fermi gas along a crossover from Bardeen- Cooper- Schrieffer( BCS) superfluid to a Bose- Einstein condensate( BEC). Based on the superfluid hydrodynamic equations we derive a Kadomtsev-Petriashvili equation with positive dispersion describing weak nonlinear excitations,under the quasi two- dimension( 2D) and long- wavelength approximations. We present 2D soliton solutions in the BCS- BEC crossover,and numerical results for the dynamics of solitons in the presence of the trapping potential. It is shown that the high- depth dark solitons decay into a large number of vortex- antivortex pairs due to the snake( transverse) instability,which display different behaviors in different superfluid regimes.更多还原