title: Quantum Hamiltonian identification from measurement time traces.
abstract: Precise identification of parameters governing quantum processes is a critical task for quantum information and communication technologies. In this Letter, we consider a setting where system evolution is determined by a parametrized Hamiltonian, and the task is to estimate these parameters from temporal records of a restricted set of system observables (time traces). Based on the notion of system realization from linear systems theory, we develop a constructive algorithm that provides estimates of the unknown parameters directly from these time traces. We illustrate the algorithm and its robustness to measurement noise by applying it to a one-dimensional spin chain model with variable couplings.
authors.affiliation: Joint Institute of UM-SJTU and Key Laboratory of System Control and Information Processing (MOE), Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Scalable and Secure Systems Research (08961), Sandia National Laboratories, Livermore, California 94550, USA.
authors.forename: Mohan
authors.initials: M
authors.lastname: Sarovar