Probing a quantum field in a photon box
J. M. Raimond, Tristan Meunier, Patrice Bertet, S. Gleyzes, Paolo Maioli, Alexia Auffèves, Gilles Nogues, M. Brune, S. Haroche · Journal of Physics B Atomic Molecular and Optical Physics · 2005
Einstein often performed thought experiments with 'photon boxes', storing fields for unlimited times. This is yet but a dream. We can nevertheless store quantum microwave fields in superconducting cavities for billions of periods. Using circular Rydberg atoms, it is possible to probe in a very detailed way the quantum state of these trapped fields. Cavity quantum electrodynamics tools can be used for a direct determination of the Husimi Q and Wigner quasi-probability distributions. They provide a very direct insight into the classical or non-classical nature of the field.