Theory and applications of photon-atom interactions in quantum information

Pieter Kok, Brendon W. Lovett

Carlos R. Stroud

Abstract : The Center for Quantum Information (CQI) is a multidisciplinary research center for the study of the processing and transmittal of information using quantum systems. The major goals of the center are to develop a toolbox of quantum procedures and protocols in a variety of elementary systems, ranging from atoms and molecules to photons and electronic nanostructures, and to formulate the elements of a quantum theory of information. To achieve these aims, CQI is based upon the interaction of several highly interdisciplinary research projects. The Center is a collaborative effort of nine professors from five universities (Rochester, Harvard, Stanford, Cornell, and Rutgers). Expertise ranges from quantum optics and atomic physics, through mesoscopic electronics, to information theory and its applications in commercial optical telecommunications systems,

Kunihiro Kojima, Holger Friedrich Hofmann, Shigeki Takeuchi +1 more

The nonlinear photon-photon interaction mediated by a single two-level atom is studied theoretically based on a one-dimensional model of the field-atom interaction. This model allows us to determine the effects of an atomic nonlinearity on the spatiotemporal coherence of a two-photon state. Specifically, the complete two-photon output wave function can be obtained for any two-photon input wave function. It is shown that the quantum interference between the components of the output state associated with different interaction processes causes bunching and antibunching in the two-photon statistics. This theory may be useful for various applications in photon manipulation, e.g., quantum information processing using photonic qubits, quantum nondemolition measurements, and the generation of entangled photons.

Christopher R. Monroe

Jian Cheng Yang, Paul G. Kwiat

We study photon-photon interactions mediated by a cavity-atom system in the strongcoupling regime of cavity quantum electrodynamics (QED). Different temporal shapes of the incident photons have been explored via numerical calculations. Especially, time-reversed photons can be in the cavity simultaneously and potentially acquire strong interaction with each other, advancing quantum information applications, e.g., quantum non-demolition (QND) measurement.

Young‐Wook Cho