Decoherence of encoded quantum registers

TL;DR

This paper investigates how encoding quantum information in decoherence-free subspaces can protect quantum registers from decoherence, providing analytical results for fidelity in both dissipation-less and dissipative spin-boson models.

Contribution

It offers explicit analytical expressions for the fidelity of encoded quantum registers in spin chains interacting with a bosonic bath, including dissipative effects.

Findings

Encoding improves quantum register fidelity under decoherence.

Analytical results compare plain and encoded register performance.

Dissipative effects modeled with Bloch-Redfield master equation.

Abstract

In order to eliminate disturbing effects of decoherence, encoding of quantum information in decoherence-free subspaces has been suggested. We analyze the benefits of this concept for a quantum register that is realized in a spin chain in contact with a common bosonic bath. Within a dissipation-less model we provide explicit analytical results for the average fidelity of plain and encoded quantum registers. For the investigation of dissipative spin-boson couplings we employ a master equation of Bloch-Redfield type.