Quantum instability in a dc-SQUID with strongly asymmetric dynamical parameters

TL;DR

This paper investigates how a hybrid classical-quantum system, modeled as an asymmetric dc-SQUID, can escape a metastable state via a sequential tunneling and potential distortion process called the 'Muenchhausen effect'.

Contribution

It introduces the concept of the 'Muenchhausen effect' in a dc-SQUID with asymmetric parameters and maps its dynamical phase diagram for different configurations.

Findings

Identification of the 'Muenchhausen effect' in a dc-SQUID system.

Mapping of the dynamical phase diagram for various junction parameters.

Demonstration of quantum-induced escape mechanisms in classical-quantum hybrid systems.

Abstract

A classical system cannot escape out of a metastable state at zero temperature. However, a composite system made from both classical and quantum degrees of freedom may drag itself out of the metastable state by a sequential process. The sequence starts with the tunneling of the quantum component which then triggers a distortion of the trapping potential holding the classical part. Provided this distortion is large enough to turn the metastable state into an unstable one, the classical component can escape. This process reminds of the famous baron Muenchhausen who told the story of rescuing himself from sinking in a swamp by pulling himself up by his own hair--we thus term this decay the `Muenchhausen effect'. We show that such a composite system can be conveniently studied and implemented in a dc-SQUID featuring asymmetric dynamical parameters. We determine the dynamical phase diagram of this system for various choices of junction parameters and system preparations.