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Faculty publications – Physics

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Full-Text Articles in Physics

Timing Of Pair Production In Time-Dependent Force Fields, Christopher C. Gerry, Q Su, Rainer Grobe Oct 2006

Timing Of Pair Production In Time-Dependent Force Fields, Christopher C. Gerry, Q Su, Rainer Grobe

Faculty publications – Physics

We examine the creation and annihilation dynamics for electron-positron pairs in a time-dependent but subcritical electric force using a simplified model system. Numerical and semianalytical solutions to computational quantum field theory show that despite the continuity of the quantum field operator in time, the actual number of created particles can change in a discontinuous way if the field changes abruptly. The number of permanently created particles after the pulse, however, increases continuously with the duration of the electric field pulse, suggesting a transition from an exclusive annihilation to a creation regime.


Interpretational Difficulties In Quantum Field Theory, P Krekora, Q Su, Rainer Grobe Feb 2006

Interpretational Difficulties In Quantum Field Theory, P Krekora, Q Su, Rainer Grobe

Faculty publications – Physics

Based on space-time-resolved solutions to relativistic quantum field theory we illustrate interpretational difficulties in associating field-theoretical quantities with properties of particles. These difficulties are related to the fact that the definition of the spatial probability density of particles depends on the choice of the Hilbert subspace on which the field operator is projected. We illustrate these problems by analyzing pair-production probabilities and spatial densities for the electron-positron dynamics associated with a spatially localized subcritical potential that is turned on and off in time.