Tachyon Condensation and Brane Annihilation in Bose-Einstein Condensates: Spontaneous Symmetry Breaking in Restricted Lower-dimensional Subspace

TL;DR

This paper explores the analogy between tachyon condensation in brane cosmology and domain wall annihilation in Bose-Einstein condensates, highlighting spontaneous symmetry breaking and vortex formation in lower-dimensional subspaces.

Contribution

It introduces a novel analogy between brane annihilation and domain wall dynamics in Bose-Einstein condensates, proposing experimental avenues for observing spontaneous symmetry breaking phenomena.

Findings

Analogous process of brane annihilation in BECs modeled as ferromagnetic ordering.

Formation of vortices from domain-wall annihilation as kink formation.

Proposal to create vorton via vortex string bridging in BEC systems.

Abstract

In brane cosmology, the Big Bang is hypothesized to occur by the annihilation of the brane-anti-brane pair in a collision, where the branes are three-dimensional objects in a higher-dimensional Universe. Spontaneous symmetry breaking accompanied by the formation of lower-dimensional topological defects, e.g. cosmic strings, is triggered by the so-called `tachyon condensation', where the existence of tachyons is attributable to the instability of the brane-anti-brane system. Here, we discuss the closest analogue of the tachyon condensation in atomic Bose-Einstein condensates. We consider annihilation of domain walls, namely branes, in strongly segregated two-component condensates, where one component is sandwiched by two domains of the other component. In this system, the process of the brane annihilation can be projected effectively as ferromagnetic ordering dynamics onto a two-dimensional space. Based on this correspondence, three-dimensional formation of vortices from a domain-wall annihilation is considered to be a kink formation due to spontaneous symmetry breaking in the two-dimensional space. We also discuss a mechanism to create a `vorton' when the sandwiched component has a vortex string bridged between the branes. We hope that this study motivates experimental researches to realize this exotic phenomenon of spontaneous symmetry breaking in superfluid systems.