1302.5239 (M. A. Yurischev)

Quantum discord of two-qubit CS states: Analytical solution    [PDF]

M. A. Yurischev

It is found an universal local unitary (orthogonal) transformation which transforms any centrosymmetric (CS) density matrix \rho_{CS} into the X density matrix \rho_X: H\otimes H\rho_{CS}H\otimes H=\rho_X, where H is the Hadamard transformation. Because quantum discord is invariant under the local unitary transformations, this remarkable property allows to get the discord of general two-qubit CS states in the analytical form using the corresponding well-known formulas for the X states. Examples of systems with CS density matrices provided from the recent literature, including XXZ spin model with the Dzyaloshinsky-Moriya interaction and a gas of spin-carrying particles in closed nanopore.

View original: http://arxiv.org/abs/1302.5239