论文标题
兰道不稳定和孤子形成
Landau Instability and soliton formation
论文作者
论文摘要
考虑在有限温度下$ t $ t $ a超流体移动，速度$ v $相对于热浴或其正常组件。从Landau的论点中，存在着一个关键的$ V_C（T）$，超过该$，可以自发产生激发，并且系统变得不稳定。确定这种不稳定引起的最终状态一直是一个杰出的公开问题。使用全息二元性，我们对初始不稳定状态的演变进行动态模拟，并发现该系统沉降到均匀的超流体状态，最终速度低于临界速度。动态进化过程似乎是高度混乱的，表现出瞬时湍流。然而，我们能够从模拟中鉴定出从孤子的自发成核方面，一种普遍的物理机制来降低超流速速度。我们还得出了一个简单的分析公式，该公式将最终速度与进化过程中成核的孤子数量相关联。
Consider at a finite temperature $T$ a superfluid moving with a velocity $v$ relative to the thermal bath or its normal component. From Landau's argument there exists a critical $v_c (T)$ beyond which excitations can be spontaneously generated and the system becomes unstable. Identifying the final state induced by such an instability has been an outstanding open question. Using holographic duality we perform dynamical simulations of evolutions from initial unstable states, and find that the system settles to a homogenous superfluid state with a final velocity below the critical velocity. The dynamical evolution process appears to be highly chaotic, exhibiting transient turbulence. Nevertheless we are able to identify from the simulations a universal physical mechanism for the reduction of superfluid velocity, in terms of spontaneous nucleation of solitons. We also derive a simple analytic formula which relates the final velocity to the number of solitons nucleated during the evolution.
