Studying topological defects and symmetry-breaking transitions in spinor Bose-Einstein condensates

Speaker: Guillaume Gauthier
Affiliation: University of Queensland

Abstract

There are few quantum fluids in nature in which the macroscopic characteristics of the fluid is directly described by the quantum coherences and even few systems in which nontrivial internal degrees of freedom can be accessed and studied. Spinor gases are a recent addition to the toolbox of such system, which previously included d-wave, p-wave superconductor and certain phases of superfluid 3He. Ultracold gases below their critical temperature typically display superfluidity and the extra spin component adds aspects of magnetism both of which contain aspects of quantum phase coherence, long-range order and symmetry breaking. This leads to an interplay between the two phenomena leading to a wealth of topological defects such as vortices (polar-core, solitonic, half quantum, coreless), skyrmions, quantum knots and monopoles. My talk will present the current project we are working towards in the atom optics lab, which seeks to understand and manipulate spin vortices in a magnetic quantum fluid. The focus of the talk will be on presenting the fundamental understanding of the basics properties of these spinor gases and the open questions we hope to answer with this project. The experimental progress made towards our aims, of controllably creating spinor gases in quasi-2D to 2D regime in which topological defects such as polar-core vortices and symmetry-breaking transitions can be studied, will be presented.