Strong micro-macro entanglement from a weak cross-Kerr nonlinearity

TL;DR

This paper demonstrates that strong micro-macro entanglement can be generated using a weak cross-Kerr nonlinearity by employing a large amplitude for the macroscopic beam, with analysis of loss effects and experimental detection methods.

Contribution

It shows that weak nonlinearities can produce significant micro-macro entanglement with large macroscopic amplitudes, advancing quantum optics experiments.

Findings

Strong entanglement achievable with weak phase shifts

Analysis of loss effects on entanglement

Proposed experimental detection methods

Abstract

We study the entanglement generated by a weak cross-Kerr nonlinearity between two initial coherent states, one of which has an amplitude close to the single-photon level, while the other one is macroscopic. We show that strong micro-macro entanglement is possible for weak phase shifts by choosing the amplitude of the macroscopic beam sufficiently large. We analyze the effects of loss and discuss possible experimental demonstrations of the micro-macro entanglement based on homodyne tomography and on a new entanglement witness.