研究業績

he wake generated by an object moving through a fluid depends on the size and velocity of the obstacle and is associated with various physical phenomena such as vortex formation and turbulent transition. The wake has been studied experimentally and theoretically in superfluids. In cold atomic systems, optical potentials have been used in superfluid wake experiments [1-2]. In numerical simulations [3-4], Gaussian potential is often assumed as obstacles. However, the dynamics of the wake and the critical velocity for vortex formation depend on the specifics of the obstacle potential, complicating the universal discussion. Plate obstacle is comparatively easy to handle both theoretically and numerically. The size of the obstacle can be characterized only by the width of the plate, making it easy to study its effects.In this study, the size dependence of the critical velocity for quantum vortex formulation in the wake of a 2D Bose-Einstein condensate with the plate obstacle is investigated. [1]Woo Jin Kwon, Joon Hyun Kim, Sang Won Seo, and Y. Shin, Phys. Rev. Lett. 117, 245301 (2016) [2]Younghoon Lim, et al, New J. Phys. 24, 083020 (2022) [3]Kazuki Sasaki, Naoya Suzuki, and Hiroki Saito, Phys. Rev. Lett. 104, 150404 (2010) [4]M. T. Reeves, et al, Phys. Rev. Lett. 114, 155302 (2015)