Experimental protocol for qubit-environment entanglement detection

TL;DR

This paper presents an experimental protocol to detect qubit-environment entanglement using a photonic quantum channel simulator, demonstrating its practicality and relevance for understanding decoherence in quantum systems.

Contribution

It introduces a tailored experimental scheme for witnessing qubit-environment entanglement in a photonic setup, advancing practical detection methods.

Findings

Successful implementation of QEE detection in a photonic simulator

Controlled environment input states to test entanglement occurrence

Validation of the technique's usefulness and experimental relevance

Abstract

Decoherence is a manifestation of the coupling of a system with its environment. The resulting loss of information can hamper the functioning of quantum devices, hence the need of understanding its origin and dynamics. Decoherence can stem from entanglement, but it can also be classical in nature. Indeed, methods have been developed to understand whether qubit-environment entanglement (QEE) is actually present in some important classes of quantum channels - pure dephasing. Their practicality resides in the fact they only require accessing the system qubit. In this article we show an implementation of this technique in a photonic quantum channel simulator via a scheme that has been tailored to the system under study. By controlling the input state of the environment in our simulation, we can check the occurrence of qubit environment entanglement in simple, yet insightful test cases. Our results showcase the usefulness and experimental relevance of the QEE witnessing technique.