31.30.+c Characterization of quantum channels

A note on coherence power of N-dimensional unitary operators

Date: 
2015-10-22
Author(s): 

M. García-Díaz, D. Egloff, M.B. Plenio

Reference: 

arXiv:1510.06683

The coherence power of a quantum channel, that is, its ability to increase the coherence of input states, is a fundamental concept within the framework of the resource theory of coherence. In this note we discuss various possible definitions of coherence power. Then we prove that the coherence power of a unitary operator acting on a qubit, computed with respect to the l1-coherence measure, can be calculated by maximizing its coherence gain over pure incoherent states.

Interfacing GHz-bandwidth heralded single photons with a room-temperature Raman quantum memory

Date: 
2014-05-27
Author(s): 

P. S. Michelberger, T. F. M. Champion, M. R. Sprague, K. T. Kaczmarek, M. Barbieri, X. M. Jin, D. G. England, W. S. Kolthammer, D. J. Saunders, J. Nunn, I. A. Walmsley

Reference: 

quant-ph > arXiv:1405.1470

Photonics is a promising platform for quantum technologies. However, photon sources and two-photon gates currently only operate probabilistically. Large-scale photonic processing will therefore be impossible without a multiplexing strategy to actively select successful events.

Full counting statistics of Luttinger liquid conductor

Date: 
2010-12-13
Author(s): 

D. Gutman, Y. Gefen, and A. Mirlin

Reference: 

Phys. Rev. Lett. 105, 256802 (2010)

Nonequilibrium bosonization technique is used to study current fluctuations of interacting electrons in a single-channel quantum wire representing a Luttinger liquid (LL) conductor. An exact expression for the time resolved full counting statistics of the transmitted charge is derived. It is given by the Fredholm determinant of the counting operator with a time-dependent scattering phase. The result has a form of counting statistics of noninteracting particles with fractional charges, induced by scattering off the boundaries between the LL wire and the noninteracting leads.

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