The capacity of transmitting atomic qubit with light

TL;DR

This paper analyzes the quantum capacity of transmitting atomic qubits via light, showing that the channel remains degradable under certain decay conditions and deriving a formula for its capacity.

Contribution

It introduces a single-letter formula for the quantum capacity of a photon-atom transfer channel considering atomic and photon decay effects.

Findings

The channel remains degradable despite atomic and photon decay.

A single-letter formula for quantum capacity is derived.

Quantum capacity is characterized under realistic decay conditions.

Abstract

The quantum information transfer between a single photon and a two-level atom is considered as a part of a quantum channel. The channel is a degradable channel even when there are decays of the atomic excited state and the single photon state, as far as the total excitation of the combined initial state does not exceed 1. The single letter formula for quantum capacity is obtained.