标题： 逆流导致局部相互作用超流体中的罗顿谱 显示英文标题

标题： Counterflow leads to roton spectra in locally interacting superfluids

摘要： 强相互作用量子流体，如氦-II的动态与稀疏、接触相互作用的原子玻色-爱因斯坦凝聚体的根本不同。 最显著的是，具有有限范围相互作用的超流体可以支持具有类似旋子色散的激发，在有限波数处表现出最小值。 在这里，我们介绍一种机制，通过该机制，旋子谱可以在没有非局部相互作用的超流体中出现，而是由两个反向流动的零范围相互作用凝聚体的集体激发产生。 由于我们的机制仅依赖于经典场的非线性动力学，这项工作为在由耦合非线性薛定谔方程支配的广泛物理系统中实现旋子动力学打开了大门。 显示英文摘要

摘要： The dynamics of strongly interacting quantum fluids such as Helium II are fundamentally distinct from those of dilute, contact-interacting atomic Bose-Einstein condensates. Most dramatically, superfluids with finite-range interactions can support excitations with a roton-like dispersion, exhibiting a minimum at finite wavenumber. Here we introduce a mechanism through which roton spectra can emerge in superfluids without any nonlocal interactions, instead resulting from the collective excitations of two counterflowing, zero-range interacting condensates. As our mechanism relies only on the nonlinear dynamics of classical fields, this work opens the door to the realization of roton dynamics in the broad class of physical systems governed by coupled nonlinear-Schr\"odinger equations.