Channel Capacities of an Exactly Solvable Spin-Star System

TL;DR

This paper calculates the quantum channel capacities of a solvable spin star system, revealing how they depend on system parameters and showing periodic noiseless behavior under certain conditions.

Contribution

It provides exact calculations of entanglement-assisted and unassisted capacities for a non-Markovian quantum dephasing model, highlighting parameter-dependent behaviors.

Findings

Capacities depend on bath spin coupling, temperature, and size.

Channel becomes periodically noiseless with equal couplings and frequencies.

Capacities show strong non-Markovian effects.

Abstract

We calculate the entanglement-assisted and unassisted channel capacities of an exactly solvable spin star system, which models the quantum dephasing channel. The capacities for this non-Markovian model exhibit a strong dependence on the coupling strengths of the bath spins with the system, the bath temperature, and the number of bath spins. For equal couplings and bath frequencies, the channel becomes periodically noiseless.