How does an interacting many-body system tunnel through a potential barrier to open space?

TL;DR

This paper investigates quantum many-body tunneling in ultracold atomic gases, revealing how interactions and correlations influence decay processes through detailed numerical solutions of the Schrödinger equation.

Contribution

It provides a full, numerically exact analysis of many-body tunneling in a controlled one-dimensional system, highlighting the role of correlations and interference effects.

Findings

Many-body correlations significantly affect tunneling dynamics.

Quantum interference of single-particle tunneling processes is crucial.

The study connects tunneling phenomena to atom lasers and ionization processes.

Abstract

The tunneling process in a many-body system is a phenomenon which lies at the very heart of quantum mechanics. It appears in nature in the form of alpha-decay, fusion and fission in nuclear physics, photoassociation and photodissociation in biology and chemistry. A detailed theoretical description of the decay process in these systems is a very cumbersome problem, either because of very complicated or even unknown interparticle interactions or due to a large number of constitutent particles. In this work, we theoretically study the phenomenon of quantum many-body tunneling in a more transparent and controllable physical system, in an ultracold atomic gas. We analyze a full, numerically exact many-body solution of the Schr\"odinger equation of a one-dimensional system with repulsive interactions tunneling to open space. We show how the emitted particles dissociate or fragment from the trapped and coherent source of bosons: the overall many-particle decay process is a quantum interference of single-particle tunneling processes emerging from sources with different particle numbers taking place simultaneously. The close relation to atom lasers and ionization processes allows us to unveil the great relevance of many-body correlations between the emitted and trapped fractions of the wavefunction in the respective processes.