Postselection induced entanglement swapping from a vacuum--excitation entangled state to separate quantum systems

TL;DR

This paper demonstrates how a single particle in superposition can entangle two separate objects, with maximum entanglement at intermediate coupling, and explores the quantum Cheshire cat phenomenon.

Contribution

It introduces a novel method of entangling separate quantum systems via a single particle in superposition, highlighting the role of intermediate coupling strengths.

Findings

Maximum entanglement occurs at intermediate coupling strengths.

The quantum Cheshire cat phenomenon is realized with detectors measuring presence and polarization.

Entanglement can be generated from a vacuum--excitation entangled state.

Abstract

We show that a single particle in a superposition of different paths can entangle two objects located on each path. The entanglement has its maximum visibility for intermediate coupling strengths. In particular, when the two quantum systems with which the particle interacts are detectors that measure its presence and its polarization, the so-called quantum Cheshire cat is realized.