Increasing and decreasing entanglement characteristics for continuous variables by a local photon subtraction

TL;DR

This paper explores how local photon subtraction can both increase certain quantum correlations and decrease entanglement in non-Gaussian continuous-variable states, with implications for quantum teleportation.

Contribution

It demonstrates the counterintuitive effects of local photon subtraction on entanglement and quantum correlations in non-Gaussian states generated by beam splitters.

Findings

Photon subtraction enhances quantum teleportation performance.

Photon subtraction decreases entanglement degree.

Effects are most prominent at small amplitudes.

Abstract

We investigate how the entanglement characteristics of a non-Gaussian entangled state are increased or decreased by a local photon subtraction operation. The non-Gaussian entangled state is generated by injecting a single-mode non-Gaussian state and a vacuum state into a 50:50 beam splitter. We consider a photon-added coherent state and an odd coherent state as a single-mode non-Gaussian state. In the regime of small amplitude, we show that the performance of quantum teleportation and the second-order Einstein-Podolsky- Rosen-type correlation can both be enhanced, whereas the degree of entanglement decreases, for the output state when a local photon subtraction operation is applied to the non-Gaussian entangled state. The counterintuitive effect is more prominent in the limit of nearly zero amplitude.