Continuous Quantum Error Correction Through Local Operations

TL;DR

This paper introduces local quantum error correction protocols using environment measurements and feedback control with qutrits, enabling deterministic protection of global quantum resources like entanglement in dissipative systems.

Contribution

It presents novel local strategies employing environment measurements and qutrit encoding to fully protect global quantum information, including entanglement, in dissipative environments.

Findings

Protocols effectively protect entanglement against dissipation.

Qutrit encoding enhances error correction capabilities.

Methods prevent entanglement sudden death and can even increase entanglement.

Abstract

We propose local strategies to protect global quantum information. The protocols, which are quantum error correcting codes for dissipative systems, are based on environment measurements, direct feedback control and simple encoding of the logical qubits into physical qutrits whose decaying transitions are indistinguishable and equally probable. The simple addition of one extra level in the description of the subsystems allows for local actions to fully and deterministically protect global resources, such as entanglement. We present codes for both quantum jump and quantum state diffusion measurement strategies and test them against several sources of inefficiency. The use of qutrits in information protocols suggests further characterization of qutrit-qutrit disentanglement dynamics, which we also give together with simple local environment measurement schemes able to prevent distillability sudden death and even enhance entanglement in situations in which our feedback error correction is not possible.