Interference dislocations in condensate of indirect excitons

TL;DR

This paper reports the discovery of unique interference dislocations in a condensate of indirect excitons, which are caused by converging matter waves rather than traditional phase defects like vortices.

Contribution

It introduces a new type of phase singularity in quantum condensates, distinct from known vortices and skyrmions, arising from converging matter waves.

Findings

Dislocations observed in interference patterns are not linked to conventional phase defects.

The dislocations originate from converging condensate matter waves.

The study enhances understanding of phase singularities in quantum condensates.

Abstract

Phase singularities in quantum states play a significant role both in the state properties and in the transition between the states. For instance, a transition to two-dimensional superfluid state is governed by pairing of vortices and, in turn, unpaired vortices can cause dissipations for particle fluxes. Vortices and other phase defects can be revealed by characteristic features in interference patterns produced by the quantum system. We present dislocation-like phase singularities in interference patterns in a condensate of indirect excitons measured by shift-interferometry. We show that the observed dislocations in interference patterns are not associated with conventional phase defects: neither with vortices, nor with polarization vortices, nor with half-vortices, nor with skyrmions, nor with half-skyrmions. We present the origin of these new phase singularities in condensate interference patterns: the observed interference dislocations originate from converging of the condensate matter waves propagating from different sources.