Decoherence-Free Subspaces for Multiple-Qubit Errors: (I) Characterization
Abstract
Coherence in an open quantum system is degraded through its interaction with a bath. This decoherence can be avoided by restricting the dynamics of the system to special decoherence-free subspaces. These subspaces are usually constructed under the assumption of spatially symmetric system-bath coupling. Here we show that decoherence-free subspaces may appear without spatial symmetry. Instead, we consider a model of system-bath interactions in which to first order only multiple-qubit coupling to the bath is present, with single-qubit system-bath coupling absent. We derive necessary and sufficient conditions for the appearance of decoherence-free states in this model, and give a number of examples. In a sequel paper we show how to perform universal and fault tolerant quantum computation on the decoherence-free subspaces considered in this paper.
Cite
@article{arxiv.quant-ph/9908064,
title = {Decoherence-Free Subspaces for Multiple-Qubit Errors: (I) Characterization},
author = {Daniel A. Lidar and Dave Bacon and Julia Kempe and K. B. Whaley},
journal= {arXiv preprint arXiv:quant-ph/9908064},
year = {2016}
}
Comments
18 pages, no figures. Major changes. Section on universal fault tolerant computation removed. This section contained a crucial error. A new paper [quant-ph/0007013] presents the correct analysis