Andreev reflection in bosonic condensates

TL;DR

This paper investigates Andreev reflection phenomena at a normal-superfluid interface in bosonic condensates, revealing novel reflected atom contributions and unique reflection properties differing from traditional expectations.

Contribution

It introduces a bosonic analog of Andreev reflection, modeling the process at a normal-superfluid interface and identifying new reflected atom components with distinct velocities.

Findings

Discovered a novel reflected atom contribution in bosonic condensates.

Found that Andreev reflection in this context is neither purely specular nor conjugate.

Identified differences in group velocities of reflected components.

Abstract

We study the bosonic analog of Andreev reflection at a normal-superfluid interface where the superfluid is a boson condensate. We model the normal region as a zone where nonlinear effects can be neglected. Against the background of a decaying condensate, we identify a novel contribution to the current of reflected atoms. The group velocity of this Andreev reflected component differs from that of the normally reflected one. For a three-dimensional planar or two-dimensional linear interface Andreev reflection is neither specular nor conjugate.