# Gaussification and entanglement distillation of continuous-variable systems: a unifying picture.

@article{Campbell2012GaussificationAE, title={Gaussification and entanglement distillation of continuous-variable systems: a unifying picture.}, author={Earl T. Campbell and Jens Eisert}, journal={Physical review letters}, year={2012}, volume={108 2}, pages={ 020501 } }

Distillation of entanglement using only Gaussian operations is an important primitive in quantum communication, quantum repeater architectures, and distributed quantum computing. Existing distillation protocols for continuous degrees of freedom are only known to converge to a Gaussian state when measurements yield precisely the vacuum outcome. In sharp contrast, non-Gaussian states can be deterministically converted into Gaussian states while preserving their second moments, albeit by usually…

## 10 Citations

Continuous-variable entanglement distillation by cascaded photon replacement

- Physics
- 2020

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…

Efficient entanglement distillation without quantum memory

- PhysicsNature communications
- 2016

The theory for an efficient iterative entanglement distillation protocol without quantum memories is presented and a proof-of-principle experimental demonstration is provided, which is particularly promising for enhancing continuous-variable quantum key distribution.

Roles of thermal noise and detector efficiency in distillation of continuous variable entanglement state

- Physics
- 2013

We address the degradation of continuous variable (CV) entanglement distillation in the presence of thermal environment and nonunity detecting efficiency. We explore the logarithmic negativity as a…

Repeaters for continuous-variable quantum communication

- PhysicsPhysical Review A
- 2018

A design for continuous-variable quantum repeaters that can distribute entangled and pure two-mode squeezed states over arbitrarily long distances with a success probability that scales only polynomially with distance is presented.

Entanglement enhancement in multimode integrated circuits

- PhysicsPhysical Review A
- 2018

The faithful distribution of entanglement in continuous variable systems is essential to many quantum information protocols. As such, entanglement distillation and enhancement schemes are a…

Rate limits in quantum networks with lossy repeaters

- ArtPhysical Review Research
- 2022

Riccardo Laurenza,1 Nathan Walk,1, 2 Jens Eisert,1, 3, 4 and Stefano Pirandola5 Dahlem Center for Complex Quantum Systems, Freie Universität Berlin, 14195 Berlin, Germany Toshiba Research Europe…

Hybrid quantum key distribution network

- Computer ScienceScience China Information Sciences
- 2022

The presented hybrid QKD networks meet the low cost and compact requirement of a realistic QKKD network and provide a feasible solution for future real QKd networks by combining the advantages of both CV and DVQKD systems.

Adjonction cohérente itérative de photons pour la génération d'états quantiques mésoscopiques du champ électromagnétique

- Mathematics
- 2014

Cette these porte sur la generation d'etats quantiques mesoscopiques arbitraires de la lumiere par l'utilisation iteree d'un protocole elementaire simple, base sur un procede d'adjonction coherente…

Multi-step two-copy distillation of squeezed states via two photon subtraction

- Physics
- 2022

Squeezed states of light have been improving the sensitivity of gravitational-wave observatories and are nonclassical resources of quantum cryptography and envisioned photonic quantum computers. The…

## References

SHOWING 1-10 OF 62 REFERENCES

Gaussian transformations and distillation of entangled Gaussian states.

- Computer SciencePhysical review letters
- 2002

We prove that it is impossible to distill more entanglement from a single copy of a two-mode bipartite entangled Gaussian state via local Gaussian operations and classical communication. More…

Distilling Gaussian states with Gaussian operations is impossible.

- Computer SciencePhysical review letters
- 2002

We show that no distillation protocol for Gaussian quantum states exists that relies on (i) arbitrary local unitary operations that preserve the Gaussian character of the state and (ii) homodyne…

Distillation and purification of symmetric entangled Gaussian states

- Physics
- 2010

We propose an entanglement distillation and purification scheme for symmetric two-mode entangled Gaussian states that allows to asymptotically extract a pure entangled Gaussian state from any input…

Entanglement distillation from Gaussian input states

- Physics, Computer Science
- 2010

This work demonstrates, for the first time, such distillation from Gaussian input states, realized by the implementation of non-Gaussian operations, resulting in a large gain in entanglement.

Extremality of Gaussian quantum states.

- Computer SciencePhysical review letters
- 2006

It is proved that for every given covariance matrix the distillable secret key rate and the entanglement, if measured appropriately, are minimized by Gaussian states, implying that Gaussian encodings are optimal for the transmission of classical information through bosonic channels, if the capacity is additive.

Quantum repeaters based on atomic ensembles and linear optics

- Physics
- 2009

The theoretical and experimental status quo of this very active field of quantum repeater protocols is reviewed, and the potentials of different approaches are compared quantitatively, with a focus on the most immediate goal of outperforming the direct transmission of photons.

Quantum repeaters based on entanglement purification

- Physics, Computer Science
- 1999

A scheme is presented that allows entanglement purification over arbitrary long channels and tolerates errors on the percent level and requires a polynomial overhead in time, and an overhead in local resources that grows only logarithmically with the length of the channel.

Limitations of quantum computing with Gaussian cluster states

- Computer Science, Physics
- 2010

It is demonstrated that even under arbitrary non-Gaussian local measurements, slabs of Gaussian cluster states of a finite width cannot carry logical quantum information, even if sophisticated encodings of qubits in continuous-variable systems are allowed for.

Hybrid quantum repeater using bright coherent light.

- PhysicsPhysical review letters
- 2006

A quantum repeater protocol for long-distance quantum communication that creates entanglement between qubits at intermediate stations of the channel by using a weak dispersive light-matter interaction and distributing the outgoing bright coherent-light pulses among the stations.

On the experimental feasibility of continuous-variable optical entanglement distillation

- Physics
- 2006

The merits of the two proposed detection schemes, namely photo-detection and homodyne detection, in the light of experimental realizations of this idea becoming more and more feasible are discussed.