One-Mode Wigner Quasi-probability Distribution Function for Entangled Coherent States Generated by Beam Splitter and Cavity QED

TL;DR

This paper develops a method to generate and analyze entangled coherent states using beam splitters and cavity QED, demonstrating that Wigner function peak distances can serve as entanglement witnesses and studying decoherence effects.

Contribution

It introduces a controllable approach for creating entangled coherent states and links Wigner function features to entanglement measures, advancing quantum state characterization.

Findings

Wigner function peak distances are sensitive to entanglement.

Concurrence correlates with Wigner function features.

Decoherence affects Wigner functions during transmission.

Abstract

In this paper, we use the displacement operator together with parity operation to construct the superposition of two coherent states. By transmitting this superposition from 50-50 beam splitter the two-mode qubit like ECS is generated. Moreover, we introduce a controllable method for producing qutrit like ECS using atom-field interaction in cavity QED and beam splitter. We will show that the distances of peaks of Wigner functions for reduced density matrices of two-mode ECS's are entanglement sensitive and can be a witness for entanglement. To confirm the results we use concurrence measure to compare bipartite entanglement of ECS's with the behavior of peaks of Wigner functions. Moreover, we investigate decoherence effects on Wigner function, arising from transmitting ECS's through noisy channels.