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Communications in Theoretical Physics

Detections of the Atomic States via the Phase Shifts of Transmitted Photons Through a Cavity

J. C. Huang, Yan‐Ling Li, Lian-Fu Wei

Published Nov 1, 2013• 0 citations
Publisher

Abstract

We propose an approach to detect an unknown quantum state of the atom(s) by measuring the phase shifts of the transmitted photons through a dispersively-coupled cavity. In the framework of the input-output theory, we derive the relations between the phase shifts of the transmitted photons and the states of the atom(s) in the cavity. It is shown that due to the dispersive interaction between the cavity and the atom(s), information about the atomic state can then be extracted by measuring the phase shifts of the transmitted photons through the cavity. The feasibility of the proposal is also discussed with the experimental parameters by numerical method.

DOI
10.1088/0253-6102/60/5/15

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Various experiments on entangled atomcavity states in cavity QED will be presented. Rydberg atoms can be coupled to a superconducting cavity either resonantly by emitting and absorbing photons, or nonresonantly, by producing a macroscopic phase shift on a coherent field injected in the cavity (single atom dispersive index effect). By sending atoms one at a time across the cavity, it is possible to use these resonant and dispersive effects to entangle atoms with each other or with the cavity field.