Entanglement purification of multi-mode quantum states

Abstract

An iterative random procedure is considered allowing an entanglement purification of a class of multi-mode quantum states. In certain cases, a complete purification may be achieved using only a single signal state preparation. A physical implementation based on beam splitter arrays and non-linear elements is suggested. The influence of loss is analyzed in the example of a purification of entangled N-mode coherent states.

Two photons co- and counterpropagating throughNcross-Kerr sites

“…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].…”

“…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…”

“…In the field of quantum computing, strong Kerr nonlinearities (χ (3) ) have been suggested for circuit-model [2] and measurement based quantum computing [3], as have weak Kerr nonlinearities [4,5]. Beyond quantum computing, cross-Kerr nonlinearities have also been proposed for all optical switching [6], generation of entangled coherent states [7], quantum teleportation [8], Fock state conversion [9], entanglement distillation [10][11][12][13], nonlinear quantum metrology [14], and quantum nondemolition (QND) detection of photon number [15]. Broadly speaking, one of the advantages of cross-Kerr interactions is that they are photon-numberpreserving, making them suitable for several of these applications.…”

Entanglement distillation for three-particleWclass states

“…Pan et al [16] found a linear optical device, a polarizing beam splitter, to take the role of the C-NOT gate. Subsequently, some other theoretical and experimental schemes for the entanglement purification have been presented [17][18][19][20][21][22][23][24].…”