The anomalous tunneling of Bose-condensate excitations

TL;DR

This paper investigates the unusual tunneling behavior of phonon excitations in Bose-Einstein condensates across potential barriers, revealing an anomalous energy-dependent transparency caused by quasiresonance interactions near high barriers.

Contribution

It introduces the concept of anomalous tunneling in Bose condensates and explains the role of quasiresonance interactions in this phenomenon, which differs from standard tunneling behavior.

Findings

Strong barriers are transparent at low excitation energies.

Transmission decreases with increasing energy, contrary to typical behavior.

Quasiresonance interactions are responsible for the anomalous tunneling effect.

Abstract

We discuss the tunneling of phonon excitations across a potential barrier separating two condensate bulks. It is shown that the strong barrier proves to be transparent for the excitations at low energy $\epsilon$. Moreover, the transmission is reduced with increasing $\epsilon$ in contrast to the standard dependence. This anomalous behavior is due to an existence of the quasiresonance interaction. The origin of this interaction is a result of the formation of the special well determined by the density distribution of condensate in the vicinity of a high barrier.