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

TL;DR

This paper shows that quantum information stored in decoherence-free subspaces remains fully protected against the loss of a single particle, offering a practical method to safeguard quantum states in photon-based systems.

Contribution

It introduces a scheme demonstrating immunity of decoherence-free subspaces to particle loss in qudit ensembles under collective decoherence, with practical photon-based implementation.

Findings

Quantum superpositions in decoherence-free subspaces are immune to one particle removal.

Protection scheme applicable to photon polarization states.

Feasible with current photon technology using quadruplets.

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.