The universe on a table top: engineering quantum decay of a relativistic scalar field from a metastable vacuum

TL;DR

This paper proposes an experimental setup using ultra-cold Bose gases to observe quantum decay of a false vacuum, providing a laboratory analog for phenomena in quantum field theory and cosmology.

Contribution

It introduces a method to simulate false vacuum decay with spinor Bose gases and demonstrates its feasibility through theoretical analysis and numerical simulations.

Findings

False vacuum decay can be observed in cold atom systems.

Numerical simulations show spontaneous bubble formation within milliseconds.

The approach is robust despite dissipation effects.

Abstract

The quantum decay of a relativistic scalar field from a metastable state ("false vacuum decay") is a fundamental idea in quantum field theory and cosmology. This occurs via local formation of bubbles of true vacuum with their subsequent rapid expansion. It can be considered as a relativistic analog of a first-order phase transition in condensed matter. Here we expand upon our recent proposal [EPL 110, 56001 (2015)] for an experimental test of false vacuum decay using an ultra-cold spinor Bose gas. A false vacuum for the relative phase of two spin components, serving as the unstable scalar field, is generated by means of a modulated linear coupling of the spin components. We analyze the system theoretically using the functional integral approach and show that various microscopic degrees of freedom in the system, albeit leading to dissipation in the relative phase sector, will not hamper the observation of the false vacuum decay in the laboratory. This is well supported by numerical simulations demonstrating the spontaneous formation of true vacuum bubbles on millisecond time-scales in two-component $^{7}$Li or $^{41}$K bosonic condensates in one-dimensional traps of $\sim100\,\mu \mathrm{m}$ size.