Tunneling decay of two interacting bosons in an asymmetric double-well potential: A spectral approach

TL;DR

This paper investigates the microscopic dynamics of two interacting bosons in an asymmetric double-well potential, revealing how tunneling behaviors transition from oscillations to decay as the well widths vary, with spectral analysis identifying conditions for pair tunneling.

Contribution

It provides a spectral approach to analyze two-boson tunneling in an asymmetric double-well, highlighting conditions for correlated pair tunneling versus uncorrelated decay.

Findings

Pair tunneling occurs for specific parameters with comparable well widths.

Uncorrelated single-particle decay dominates in broad right wells.

Spectral signatures distinguish between single- and two-particle tunneling.

Abstract

We study the full-fledged microscopic dynamics of two interacting, ultracold bosons in a one- dimensional double-well potential, through the numerically exact diagonalization of the many-body Hamiltonian. With the particles initially prepared in the left well, we increase the width of the right well in subsequent trap realizations and witness how the tunneling oscillations evolve into particle loss. In this closed system, we analyze the spectral signatures of single- and two-particle tunneling for the entire range of repulsive interactions. We conclude that for comparable widths of the two wells, pair-wise tunneling of the bosons may be realized for specific system parameters. In contrast, the decay process (corresponding to a broad right well) is dominated by uncorrelated single-particle decay.