2013/03/31 by K. Held, N. Mauser · 1 citation
Physics and Astronomy · #cond-mat.mtrl-sci #cond-mat.stat-mech #cond-mat.str-el #quant-ph
paper · pdf · doi:10.1140/epjb/e2013-40424-5
published as Eur. Phys. J. B 86, 328 (2013) · 4 pages, 1 figure, final version as to appear European Physical Journal B
arxiv created 2013/06/17 · arxiv updated 2015/06/15
The relative entropy of a correlated state and an uncorrelated reference state is a reasonable measure for the degree of correlations. A key question is however which uncorrelated state to compare to. The relative entropy becomes minimal for the uncorrelated reference state that has the same one-particle density matrix as the correlated state. Hence, this particular measure, coined nonfreeness, is unique and reasonable. We demonstrate that for relevant physical situations, such as finite temperatures or a correlation enhanced orbital splitting, other choices of the uncorrelated state, even educated guesses, overestimate correlations.