Local asymptotic normality for the estimation of dynamical parameters of an open quantum system

Local asymptotic normality for the estimation of dynamical parameters of an open quantum system

Seminar author:Jukka Kiukas

Event date and time:04/13/2015 02:30:pm

Event location:IFAE seminar room

Event contact:

Input-output formalism is a well-known framework for describing continual monitoring of a Markovian open quantum system via measurements made on its environment (typically a quantised radiation field). Mathematically, the environmental noise is described in terms of quantum stochastic Wiener processes on the field Fock space. We consider the problem of identifying and estimating unknown dynamical parameters (Hamiltonian and the quantum jump operators) from the output field state. For this purpose, we first use quantum Ito calculus to derive an information geometric structure on the set of parameters, arising from the quantum Fisher information of the output state. The geometry comes with an associated CCR-algebra, and we then show that local estimation reduces asymptotically (with long observation times) to a Gaussian estimation problem on that CCR-algebra.