Continuous-variable entanglement distillation by cascaded photon replacement

TL;DR

This paper investigates continuous-variable entanglement distillation using cascaded photon replacement, showing increased entanglement with repetitions and analyzing non-Gaussianity dependence on experimental setup, aiding quantum computation.

Contribution

It introduces a cascaded photon replacement protocol for entanglement distillation, demonstrating its effectiveness and robustness against asymmetry, and explores non-Gaussianity effects in practical arrangements.

Findings

Entanglement increases with the number of protocol repetitions.

Entanglement enhancement is insensitive to protocol asymmetry in ideal conditions.

Non-Gaussianity varies significantly with experimental setup.

Abstract

We study the entanglement distillation in continuous variable systems when a photon replacement protocol is employed. A cascaded protocol is studied and we find that the resultant entanglement increases by increasing the number of repetitions. Interestingly, the entanglement enhancement is not sensitive to the asymmetry of the protocol and gives the same result for any arrangement in the absence of loss. The non-Gaussianity of the outcome state is also studied and it is found that the non-Gaussianity of the state dramatically depends on the experimental arrangements. By providing practical information on photon replacement operation, this work is one step towards realization of universal quantum computation. In particular, in setups where deGaussifying protocols are only applicable to one of the parties.