Computing complexity measures for quantum states based on exponential families
Journal of Physics A: Mathematical and Theoretical
Given a multiparticle quantum state, one may ask whether it can be represented as a thermal state of some Hamiltonian with k-particle interactions only. The distance from the exponential family defined by these thermal states can be considered as a measure of complexity of a given state. We investigate the resulting optimization problem and show how symmetries can be exploited to simplify the task of finding the nearest thermal state in a given exponential family. We also present an algorithm
... sent an algorithm for the computation of the complexity measure and consider specific examples to demonstrate its applicability.