Jeudi 03 octobre 2013 à 10h15
Salle 234, Ecole de Physique

A stochastic path integral approach to continuous quantum measurement

Andrew Jordan, University of Rochester, USA

The process of continuous quantum measurement will be formulated in terms of a stochastic path integral encoding every possible quantum trajectory, the probability density of those trajectories, the continuous measurement results, and the state disturbance. This approach gives a new way to calculate any expectation value or correlation function of the measurement result or state. As an application, we find the most likely path the quantum state takes in its state space between a preselected and a postselected state, separated by a fixed time. We solve this problem by minimizing the stochastic action and illustrate how it is important for the theory of quantum jumping of a qubit in the Zeno measurement limit. Reference: Action principle for continuous quantum measurement, A. Chantasri, J. Dressel, A. N. Jordan, arXiv:1305.5201