Towards an experimental implementation of entanglement harvesting in superconducting circuits: effect of detector gap variation on entanglement harvesting

TL;DR

This paper models variable-gap detectors in superconducting circuits to explore entanglement harvesting, showing that entanglement can be extracted even with gap variations, especially in causally connected scenarios, paving the way for experimental realization.

Contribution

It introduces a realistic variable-gap detector model tailored for superconducting circuits and analyzes entanglement harvesting under experimental conditions.

Findings

Entanglement harvesting is possible in superconducting circuits.

Gap variations reduce entanglement harvesting in spacelike scenarios.

Causally connected detectors can still harvest entanglement.

Abstract

Motivated by the prospect of experimental implementations of entanglement harvesting in superconducting circuits, we propose a model of variable-gap particle detector that aims to bridge some of the gaps between Unruh-DeWitt (UDW) models and realistic implementations. Using parameters tailored to potential experimental setups, we investigate entanglement harvesting in both spacelike-separated and causally connected scenarios. Our findings reveal that while variations in the energy gap reduce the ability to harvest entanglement for spacelike-separated detectors, detectors in causal contact can still become entangled through their interaction with the field. Notably, our analysis shows that (due to the derivative coupling nature of the model) even for causally connected detectors, the entanglement primarily originates from the field's correlations. This demonstrates the potential for genuine entanglement harvesting in the lab and opens the door to near-future entanglement harvesting experiments in superconducting circuits.