Improving entanglement of even entangled coherent states by a coherent superposition of photon subtraction and addition

TL;DR

This paper introduces a new entangled quantum state created by applying a coherent superposition of photon subtraction and addition to enhance entanglement properties of even entangled coherent states, improving their usefulness in quantum information tasks.

Contribution

It presents a novel method of using coherent superposition of photon operations to enhance entanglement in EECS, outperforming traditional photon addition methods.

Findings

Enhanced entanglement measures and teleportation fidelity due to superposition operation

Better improvement effects compared to single and two-photon addition operations in certain regimes

Potential for improved quantum communication protocols

Abstract

A new entangled quantum state is introduced by applying local coherent superposition (ra^+ +ta) of photon subtraction and addition to each mode of even entangled coherent state (EECS) and the properties of entanglement are investigated. It is found that the Shchukin-Vogel inseparability, the degree of entanglement and the average fidelity of quantum teleportation of the EECS can be improved due to the coherent superposition operation. The effects of improvement by coherent superposition operation are better than those by single (a^+) and two-photon (a^+ b^+) addition operations under a small region of amplitude.