arXiv:quant-ph/0411067 · Journal of Physics A Mathematical and General
Purity-bounded uncertainty relations in multidimensional space—generalized purity
Mikalai U. Karelin
Abstract
Uncertainty relations for mixed quantum states (precisely, purity-bounded position–momentum relations, developed by Bastiaans and then by Man'ko and Dodonov) are studied in the general multidimensional case. An expression for a family of mixed states at the lower bound of uncertainty relation is obtained. It is shown that in the case of entropy-bounded uncertainty relations, the lower-bound state is thermal, and a transition from the one-dimensional problem to the multidimensional one is trivial. Results of numerical calculation of the relation of the lower bound for different types of generalized purity are presented. Analytical expressions for general purity-bounded relations for highly mixed states are obtained.