A study of two-qubit density matrices with fermionic purifications
Quantum Physics
2010-01-29 v1 Mathematical Physics
math.MP
Abstract
We study 12 parameter families of two qubit density matrices, arising from a special class of two-fermion systems with four single particle states or alternatively from a four-qubit state with amplitudes arranged in an antisymmetric matrix. We calculate the Wooters concurrences and the negativities in a closed form and study their behavior. We use these results to show that the relevant entanglement measures satisfy the generalized Coffman-Kundu-Wootters formula of distributed entanglement. An explicit formula for the residual tangle is also given. The geometry of such density matrices is elaborated in some detail. In particular an explicit form for the Bures metric is given.
Cite
@article{arxiv.0807.1804,
title = {A study of two-qubit density matrices with fermionic purifications},
author = {Szilárd Szalay and Péter Lévay and Szilvia Nagy and János Pipek},
journal= {arXiv preprint arXiv:0807.1804},
year = {2010}
}
Comments
21 pages, 1 figure