We provide a novel approach for characterization of quantum Hamiltonian systems via utilizing a single measurement device. Specifically, we demonstrate how external quantum correlations can be used for Hamiltonian identification tasks. We explicitly introduce experimental procedures for direct estimation of single- and two-qubit Hamiltonian parameters, and also for simultaneous estimation of transverse and longitudinal relaxation rates, using a single Bell-state analyzer. An advantage of our method over the earlier approaches is that it has a built-in feature which makes it suitable for partial characterization of Hamiltonian parameters.
@article{arxiv.0708.0436,
title = {Direct Estimation of Single- and Two-Qubit Hamiltonians and Relaxation Rates},
author = {M. Mohseni and A. T. Rezakhani and A. Aspuru-Guzik},
journal= {arXiv preprint arXiv:0708.0436},
year = {2008}
}