# Macroscopic Quantum Tunneling Escape of Bose-Einstein Condensates

## TL;DR

This paper investigates the non-exponential decay in macroscopic quantum tunneling of Bose-Einstein condensates, combining experiments with theoretical models to reveal the role of interactions and many-body effects.

## Contribution

It introduces a modified WKB model accounting for mean-field effects and compares mean-field and many-body dynamics using different simulation methods.

## Key findings

- Non-exponential decay observed in experiments
- Modified WKB model aligns with experimental data
- Many-body effects suggest limitations of mean-field theory

## Abstract

Recent experiments on macroscopic quantum tunneling reveal a non-exponential decay of the number of atoms trapped in a quasibound state behind a potential barrier. Through both experiment and theory, we demonstrate this non-exponential decay results from interactions between atoms. Quantum tunneling of tens of thousands of 87 Rb atoms in a Bose-Einstein condensate is modeled by a modified Jeffreys-Wentzel-Kramers-Brillouin model, taking into account the effective time-dependent barrier induced by the mean-field. Three-dimensional Gross-Pitaevskii simulations corroborate a mean-field result when compared with experiments. However, with one-dimensional modeling using time-evolving block decimation, we present an effective renormalized mean-field theory that suggests many-body dynamics for which a bare mean-field theory may not apply.