# Quantum entanglement distribution with hybrid parity gate

## TL;DR

This paper introduces a scheme for distributing various multi-qubit entangled states among distant atoms using a hybrid parity gate based on controlled phase-shift interactions and homodyne detection, achieving high success and fidelity.

## Contribution

It presents a novel method to generate and distribute complex entangled states across separated atoms using a hybrid parity gate with high efficiency.

## Key findings

- Successful distribution of GHZ, W, and Dicke states in one shot.
- High success probability and fidelity despite channel loss.
- Implementation of an $n$-qubit parity gate for entanglement distribution.

## Abstract

We propose a scheme for entanglement distribution among different single atoms trapped in separated cavities. In our scheme, by reflecting an input coherent optical pulse from a cavity with a single trapped atom, a controlled phase-shift gate between the atom and the coherent optical pulse is achieved. Based on this gate and homodyne detection, we construct an $n$-qubit parity gate and show its use for distribution of a large class of entangled states in one shot, including the GHZ state $\left\vert GHZ_{n}\right\rangle $, W state $\left\vert W_{n}\right\rangle $, Dicke state $\left\vert D_{n,k}\right\rangle $ and certain sums of Dicke states $% \left\vert G_{n,k}\right\rangle $. We also show such distribution could be performed with high success probability and high fidelity even in the presence of channel loss.