Estimating purity in terms of correlation functions
arXiv:quant-ph/0304103 · doi:10.1103/PhysRevA.67.062108
Abstract
We prove a rigorous inequality estimating the purity of a reduced density matrix of a composite quantum system in terms of cross-correlation of the same state and an arbitrary product state. Various immediate applications of our result are proposed, in particular concerning Gaussian wave-packet propagation under classically regular dynamics.
3 pages