skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Experimentally feasible purification of continuous-variable entanglement

Abstract

We propose a scheme for purification and distillation of squeezed and entangled continuous-variable states of light transmitted through a channel exhibiting phase fluctuations. The outstanding advantage of the suggested protocol is its experimental feasibility since it only involves an interference of two copies of the decohered state on a balanced beam splitter, a homodyne measurement on one of the output beams, and a conditioning on the measurement outcome. The purification can counteract the detrimental effects of phase fluctuations in optical quantum-communication networks.

Authors:
;  [1];  [2];  [3]
  1. Department of Optics, Palacky University, 17. listopadu 50, 77200 Olomouc (Czech Republic)
  2. School of Mathematics and Physics, The Queen's University, Belfast BT7 1NN (United Kingdom)
  3. Max-Planck-Institut fuer Gravitationsphysik (Albert-Einstein-Institut) and Universitaet Hannover, Callinstrass 38, 30167 Hannover (Germany)
Publication Date:
OSTI Identifier:
20982434
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. A; Journal Volume: 75; Journal Issue: 5; Other Information: DOI: 10.1103/PhysRevA.75.050302; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; BEAM SPLITTING; COMMUNICATIONS; INFORMATION THEORY; INTERFERENCE; LIGHT TRANSMISSION; QUANTUM DECOHERENCE; QUANTUM ENTANGLEMENT; QUANTUM MECHANICS

Citation Formats

Fiurasek, Jaromir, Filip, Radim, Marek, Petr, and Schnabel, Roman. Experimentally feasible purification of continuous-variable entanglement. United States: N. p., 2007. Web. doi:10.1103/PHYSREVA.75.050302.
Fiurasek, Jaromir, Filip, Radim, Marek, Petr, & Schnabel, Roman. Experimentally feasible purification of continuous-variable entanglement. United States. doi:10.1103/PHYSREVA.75.050302.
Fiurasek, Jaromir, Filip, Radim, Marek, Petr, and Schnabel, Roman. Tue . "Experimentally feasible purification of continuous-variable entanglement". United States. doi:10.1103/PHYSREVA.75.050302.
@article{osti_20982434,
title = {Experimentally feasible purification of continuous-variable entanglement},
author = {Fiurasek, Jaromir and Filip, Radim and Marek, Petr and Schnabel, Roman},
abstractNote = {We propose a scheme for purification and distillation of squeezed and entangled continuous-variable states of light transmitted through a channel exhibiting phase fluctuations. The outstanding advantage of the suggested protocol is its experimental feasibility since it only involves an interference of two copies of the decohered state on a balanced beam splitter, a homodyne measurement on one of the output beams, and a conditioning on the measurement outcome. The purification can counteract the detrimental effects of phase fluctuations in optical quantum-communication networks.},
doi = {10.1103/PHYSREVA.75.050302},
journal = {Physical Review. A},
number = 5,
volume = 75,
place = {United States},
year = {Tue May 15 00:00:00 EDT 2007},
month = {Tue May 15 00:00:00 EDT 2007}
}
  • We construct a set of criteria detecting genuine multipartite entanglement in arbitrary dimensional multipartite systems. These criteria are optimally suited for detecting multipartite entanglement in n-qubit Dicke states with m excitations, as shown in exemplary cases. Furthermore, they can be employed to detect multipartite entanglement in different states related to quantum cloning, decoherence-free communication, and quantum secret sharing. In a detailed analysis, we show that the criteria are also more robust to noise than any other criterion known so far, especially with increasing system size. Furthermore, it is shown that the number of required local observables scales only polynomially withmore » size, thus making the criteria experimentally feasible.« less
  • We propose two probabilistic entanglement concentration schemes for a single copy of a two-mode squeezed vacuum state. The first scheme is based on the off-resonant interaction of a Rydberg atom with the cavity field while the second setup involves the cross Kerr interaction, an auxiliary mode prepared in a strong coherent state, and homodyne detection. We show that the continuous-variable entanglement concentration allows us to improve the fidelity of teleportation of coherent states.
  • Several recent experiments have demonstrated the promise of atomic ensembles for quantum teleportation and quantum memory. In these cases, the collective internal state of the atoms is well described by continuous variables corresponding to the operators X{sub 1},P{sub 1} and the interaction with the optical field (X{sub 2},P{sub 2}) by a quadratic Hamiltonian X{sub 1}X{sub 2}. We show how this interaction can be used optimally to create entanglement and squeezing. We derive conditions for the efficient simulation of quadratic Hamiltonians and the engineering of all Gaussian operations and states.
  • We derive necessary conditions in terms of the variances of position and momentum linear combinations for all kinds of separability of a multiparty multimode continuous-variable state. Their violations can be sufficient for genuine multipartite entanglement, provided the combinations contain both conjugate variables of all modes. Hence, a complete state determination, for example, by detecting the entire correlation matrix of a Gaussian state, is not needed.