Microscopic description for the emergence of collective dissipation in extended quantum systems

TL;DR

This paper investigates how collective dissipation can occur in extended quantum systems through a microscopic model, revealing mechanisms that challenge previous assumptions and depend on system frequency and orientation.

Contribution

It provides a microscopic explanation for the emergence of collective dissipation in quantum systems, showing it can occur at large distances contrary to prior beliefs.

Findings

Collective dissipation depends on system frequency and orientation.

The cross-over between independent and collective baths is not solely distance-based.

Mechanisms differ between dephasing and dissipative baths.

Abstract

Practical implementations of quantum technology are limited by unavoidable effects of decoherence and dissipation. With achieved experimental control for individual atoms and photons, more complex platforms composed by several units can be assembled enabling distinctive forms of dissipation and decoherence, in independent heat baths or collectively into a common bath, with dramatic consequences for the preservation of quantum coherence. The cross-over between these two regimes has been widely attributed in the literature to the system units being farther apart than the bath's correlation length. Starting from a microscopic model of a structured environment (a crystal) sensed by two bosonic probes, here we show the failure of such conceptual relation, and identify the exact physical mechanism underlying this cross-over, displaying a sharp contrast between dephasing and dissipative baths. Depending on the frequency of the system and, crucially, on its orientation with respect to the crystal axes, collective dissipation becomes possible for very large distances between probes, opening new avenues to deal with decoherence in phononic baths.