Decoherence and Irreversibility: the role of the reservoir effective Hilbert space size

TL;DR

This paper explores how the effective Hilbert space size of a reservoir influences decoherence and irreversibility, showing that few degrees of freedom can mimic larger environments if their effective Hilbert spaces match.

Contribution

It introduces the concept that the effective Hilbert space size governs decoherence and irreversibility, providing a new perspective on environment simulation.

Findings

Few degrees of freedom can simulate larger environments with the same effective Hilbert space.

Effective Hilbert space size determines the environment's efficiency in causing irreversible coherence loss.

Decoherence is fundamentally linked to the reservoir's effective Hilbert space size.

Abstract

We show that decoherence is determined by the effective Hilbert space size, and demonstrate that a few degrees of freedom system can simulate a "N" degrees of freedom environment if they have the same effective Hilbert space. The effective Hilbert space size of the environment also determines its long time efficiency as generator of irreversible coherence loss.