2004/03/15 by Roman R. Zapatrin, Zapatrin, Roman R.
Physics and Astronomy · #FOS: Physical sciences #Quantum Physics (quant-ph) #quant-ph
paper · pdf · doi:10.48550/arxiv.quant-ph/0403105
LaTeX 2e, 3 PS figures, 4 pages + 3 pages appendix
arxiv created 2004/03/15 · arxiv updated 2009/12/01
Generalizing the notion of relative entropy, the difference between a priori and a posteriori relative entropy for quantum systems is drawn. The former, known as quantum relative entropy, is associated with quantum states recognition. The latter -- a posteriori relative quantum entropy is shown to be related with state reconstruction due to the following property: given a density operator ρ, ensembles of pure states with Gibbs distribution with respect to the defined distance are proved to represent the initial state ρ up to an amount of white noise (completely mixed state) which can be made arbitrary small.