Procrustean entanglement concentration of continuous-variable states of light

Menzies, David; Korolkova, Natalia

doi:10.1103/physreva.74.042315

Cited by 17 publications

(22 citation statements)

References 21 publications

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“…Further motivation and structure of the paper There are two notable problems with most of the proposed uses of cross-Kerr nonlinearities of Refs. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. arXiv:1604.03914v3 [quant-ph] 19 Aug 2016…”

Section: Introductionmentioning

confidence: 99%

Two photons co- and counterpropagating throughNcross-Kerr sites

2016

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A cross-Kerr interaction produces a phase shift on two modes of light proportional to the number of photons in both modes, and is sometimes called cross-phase modulation. Cross-Kerr nonlinearities have many applications in classical and quantum nonlinear optics, including the possibility of a deterministic and all-optical controlled-phase gate. We calculate the one-and two-photon S-matrix for fields propagating in a medium where the cross-Kerr interaction is spatially distributed at discrete interaction sites comprised of atoms. For the interactions considered, we analyze the cases where the photons co-propagate and counter-propagate through the medium and give a physical interpretation to the differences between the two cases. Finally, we obtain the S-matrix in the limit of infinitely long chains, showing that it corresponds to a perfect controlled-phase operation.

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Section: Introductionmentioning

confidence: 99%

Two photons co- and counterpropagating throughNcross-Kerr sites

2016

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“…For this reason, the option to increase entanglement in the ensembles by local operations would be greatly desired. Entanglement distillation [3,4] is a large field of research, and many different protocols have been devised for continuous variable entanglement concentration [5,6,7]. In recent years there has also been experimental success in distilling light states [8,9,10] but little is known about the possibility of distilling entanglement in atomic ensembles.…”

Section: Introductionmentioning

confidence: 99%

Entanglement concentration for two atomic ensembles using an effective atom-light beamsplitter

Tatham¹,

Korolkova²

2011

J. Phys. B: At. Mol. Opt. Phys.

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Abstract. We present a protocol for increasing the entanglement between two entangled atomic ensembles based on applying an approximate atom-light beamsplitter transformation to both ensembles. The effective asymmetric atom-light beamsplitter is created via a double-pass quantum non-demolition interaction between polarized light and a spin polarized atomic ensemble, derived from the linearised dipole interaction. The entanglement concentration protocol itself uses the procrustean method, similar to that first devised for light by Browne et al [2003 Phys. Rev. A 67 062320] and includes photon counting after the interaction as the required non-Gaussian element. We calculate the output logarithmic negativity in this scheme and show that entanglement between macroscopic ensembles can be increased with probabilities comparable with those for the light scheme even if on-off detectors of low efficiency are used.

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“…The exact meaning of this will become clear in section II. Apart from fundamental interest, we demonstrate, in section III, the calculational utility of the weak value formalism to aid in the understanding of certain entanglement concentration protocols [8,9]. When viewed in this light, Im(O W ) provides a selection criteria to constrain the ingredients {|i , Ô, |f , K} and single out working examples of the protocol.…”

Section: Introductionmentioning

confidence: 99%