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Atomic, Molecular and Optical Physics Commons

Open Access. Powered by Scholars. Published by Universities.®

2007

PHOTON

Articles 1 - 2 of 2

Full-Text Articles in Atomic, Molecular and Optical Physics

Nonlocal Entanglement Of Coherent States, Complementarity, And Quantum Erasure, Christopher C. Gerry, Rainer Grobe Mar 2007

Nonlocal Entanglement Of Coherent States, Complementarity, And Quantum Erasure, Christopher C. Gerry, Rainer Grobe

Faculty publications – Physics

We describe a nonlocal method for generating entangled coherent states of a two-mode field wherein the field modes never meet. The proposed method is an extension of an earlier proposal [C. C. Gerry, Phys. Rev. A 59, 4095 (1999)] for the generation of superpositions of coherent states. A single photon injected into a Mach-Zehnder interferometer with cross-Kerr media in both arms coupling with two external fields in coherent states produces entangled coherent states upon detection at one of the output ports. We point out that our proposal can be alternatively viewed as a "which path" experiment, and in the case …


Unitary And Nonunitary Approaches In Quantum Field Theory, K D. Lamb, Christopher C. Gerry, Rainer Grobe Jan 2007

Unitary And Nonunitary Approaches In Quantum Field Theory, K D. Lamb, Christopher C. Gerry, Rainer Grobe

Faculty publications – Physics

We use a simplified essential state model to compare two quantum field theoretical approaches to study the creation of electron-positron pairs from the vacuum. In the unitary approach the system is characterized by a state with different numbers of particles that is described by occupation numbers and evolves with conserved norm. The nonunitary approach can predict the evolution of wave functions and density operators with a fixed number of particles but time-dependent norms. As an example to illustrate the differences between both approaches, we examine the degree of entanglement for the Klein paradox, which describes the creation of an electron-positron …