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arXiv:1107.3786 · Physical Review A

Immunity of information encoded in decoherence-free subspaces to particle loss

Piotr Migdał, Konrad Banaszek

Published Nov 17, 2011• 6 citations
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Abstract

We demonstrate that for an ensemble of qudits, subjected to collective decoherence in the form of perfectly correlated random SU($d$) unitaries, quantum superpositions stored in the decoherence-free subspace are fully immune against the removal of one particle. This provides a feasible scheme to protect quantum information encoded in the polarization state of a sequence of photons against both collective depolarization and one-photon loss and can be demonstrated with photon quadruplets using currently available technology.

DOI
10.1103/physreva.84.052318

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We introduce a novel scheme for one-way quantum computing (QC) based on the use of information encoded qubits in an effective cluster state resource. With the correct encoding structure, we show that it is possible to protect the entangled resource from phase damping decoherence, where the effective cluster state can be described as residing in a decoherence-free subspace (DFS) of its supporting quantum system. One-way QC then requires either single or two-qubit adaptive measurements. As an example where this proposal can be realized, we describe an optical lattice set-up where the scheme provides robust quantum information processing. We also outline how one can adapt the model to provide protection from other types of decoherence.