Quantum state conversion by cross-Kerr interaction

Abstract

A generalized Mach-Zehnder-type interferometer equipped with crossKerr elements is proposed to convert N -photon truncated single-mode quantum states into (N +1)-mode single-photon states, which are suitable for further state manipulation by means of beam splitter arrays and ON/OFF-detections, and vice versa. Applications to the realization of unitary and non-unitary transformations, quantum state reconstruction, and quantum telemanipulation are studied.

Two photons co- and counterpropagating throughNcross-Kerr sites

“…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…”

Fast, All-Optical, Zero toπContinuously Controllable Kerr Phase Gate

“…In addition, it may also be implemented with a Kerr-effect based parity gate [19,20]. The main challenge, however, is to achieve the direct two-qubit control required for quantum information processing at the single-photon level [21][22][23][24][25]. In this case the phase control laser (reduced to the single-photon level) just becomes the second qubit photon.…”

Entanglement purification of multi-mode quantum states

“…1(a).V is a unitary single-mode oper- ator that transforms the basis states |Φ n to Fock states |n =V |Φ n , i.e., the single-mode basis {|Φ n } is supposed to be known. A realization of a desired single-mode operator or detection in a truncated space also based on beam splitter arrays, zero and single photon detections as well as cross-Kerr elements is presented in [13]. (Note that thê V are not required if attention is limited to the photon number basis.)…”