Sabotaging the harvesting of correlations from quantum fields

TL;DR

This paper investigates how additional detectors, or interlopers, can non-perturbatively sabotage the harvesting of correlations from quantum fields, revealing vulnerabilities in quantum correlation extraction processes.

Contribution

It introduces a non-perturbative analysis of correlation harvesting and demonstrates that even a single interloper can completely prevent correlation extraction between target detectors.

Findings

A single interloper can block all correlation harvesting.

Interlopers flood the field with entropy, preventing correlations.

The sabotage effect cannot be defended against.

Abstract

We study the non-perturbative harvesting of classical and quantum correlations between two parties coupled to a quantum field. First, we consider a scenario with an arbitrary number of two-level systems that couple to a quantum field locally in time. Then, we study the impact of the presence of additional detectors (interlopers) on the ability for two target detectors (Alice and Bob) to acquire correlations through their interaction with the field. We analyze the harvesting of different correlation measures in this non-perturbative regime and we demonstrate that even a single interloper can completely sabotage all correlation harvesting between Alice and Bob by acting on the causal past of one of them. Specifically, we show that the interloper is able to interact with the field so that the field itself `floods' one of the parties with entropy. This prevents Alice and Bob from acquiring any correlations. Furthermore, we show that this kind of attack cannot be defended against.