Huge quantum particle number fluctuations in a two-component Bose gas in a double-well potential

TL;DR

This paper investigates a two-component Bose gas in a double-well potential, revealing that near the phase separation transition, the particle number fluctuations become extremely large, leading to a uniform probability distribution of particle configurations.

Contribution

The study demonstrates that at the phase transition point, the ground state exhibits giant fluctuations in particle numbers, a novel insight into quantum phase transitions in multi-component Bose gases.

Findings

Huge particle number fluctuations at the transition point

Uniform probability distribution of particle configurations

Ground state characterized by large fluctuations

Abstract

Two component Bose gas in a double well potential with repulsive interactions may undergo a phase separation transition if the inter-species interactions outweigh the intra-species ones. We analyze the transition in the strong interaction limit within the two-mode approximation. Numbers of particles in each potential well are equal and constant. However, at the transition point, the ground state of the system reveals huge fluctuations of numbers of particles belonging to the different gas components. That is, probability for observation of any mixture of particles in each potential well becomes uniform.