Pure decoherence in quantum systems

TL;DR

This paper critically examines the limitations of the harmonic oscillator heat bath model in pure decoherence regimes, highlighting the role of elastic scattering and challenging recent assumptions about chaotic environments' efficiency.

Contribution

It demonstrates the inappropriateness of the harmonic oscillator model for pure decoherence and advocates elastic scattering as a fundamental mechanism, contrasting chaotic and regular environments.

Findings

Harmonic oscillator model is inadequate for pure decoherence.

Elastic scattering is identified as a key pure decoherence mechanism.

Chaotic environments may be less effective decoherers than regular ones.

Abstract

A popular model of decoherence based on the linear coupling to harmonic oscillator heat baths is analized and shown to be inappropriate in the regime where decoherence dominates over energy dissipation, called pure decoherence regime. The similar mechanism essentially related to the energy conservation implies that, on the contrary to the recent conjectures, chaotic environments can be less efficient decoherers than regular ones. Finally, the elastic scattering mechanism is advocated as the simplest source of pure decoherence.