Decoherence-free subspaces for a quantum register interacting with a spin environment

TL;DR

This paper investigates conditions for the existence of decoherence-free subspaces in a quantum spin register interacting with a spin environment, providing theoretical insights into protecting quantum information from decoherence.

Contribution

It derives conditions for low-dimensional DFS existence and characterizes high-dimensional DFS in a spin environment model.

Findings

High-dimensional DFS identified in collective decoherence limit

Necessary and sufficient conditions for low-dimensional DFS established

Framework for constructing larger DFS from smaller subspaces provided

Abstract

We study a model of a quantum spin register interacting with an environment of spin particles in quantum-measurement limit. In the limit of collective decoherence we obtain the form of state vectors that constitute high-dimensional decoherence-free subspaces (DFS). In a more general setting we present sufficient and necessary conditions for existence of low-dimensional DFSs that can be used to construct subspaces of higher dimension.