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J Schwinger

Publications and source records attributed to J Schwinger.

14 recordsLinked to original sources
PubMed1994

Casimir light: field pressure.

The electromagnetic field is assigned a self-consistent role in which abrupt slowing of the collapse produces radiation and the pressure of the radiation produces abrupt slowing. A simple expression is introduced for the photon spectrum. Conditions for light emission are proposed that imply a high degree of spatial localization. Some numerical checks are satisfied. A study of the mechanical equations of motion suggests an explanation of the very short time scale in terms of oppositely directed field pressures and the speed of light.

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PubMed1993

Casimir light: pieces of the action.

More realistic dynamics for the collapsing dielectric fluid are introduced in stages by adding contributions to the Lagrangian that forms the action. The elements are kinetic energy, Casimir potential energy, air pressure potential energy, and electromagnetic coupling to the moving dielectric. There are successful tests of partial collapse time and of minimum radius.

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PubMed1993

Casimir light: photon pairs.

Expressions are developed for weak single pair emission probability and strong emission average number of pairs. The water transparency cutoff is closely realized, showing that the fundamental time scale is even shorter.

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PubMed1993

Casimir light: the source.

The release of Casimir energy in filling a dielectric hole is identified as the source of coherent sonoluminescence. Qualitative agreement with recently acquired data is found for the magnitude and shape of the spectrum.

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PubMed1993

Casimir light: a glimpse.

Light emission produced by the reversible collapse of a cavity in a dielectric medium is given an initial, simplified treatment. The agreement between planar and spherical shapes indicates the volume nature of the effect.

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PubMed1992

Casimir energy for dielectrics: spherical geometry.

An expression is produced for the Casimir energy of a dielectric medium with a spherically symmetrical dielectric discontinuity. Tests based on dielectric and geometrical limits are successful.

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PubMed1992

Casimir energy for dielectrics.

A treatment in terms of two scalar fields supplies the electromagnetic energy of attraction between two similar dielectric slabs with parallel plane interfaces.

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PubMed1991

Phonon Green's function.

The concepts of source and quantum action principle are used to produce the phonon Green's function appropriate for an initial phonon vacuum state. An application to the Mossbauer effect is presented.

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PubMed1990

Phonon representations.

The gap between the nonlocalized lattice-phonon description and the localized Einstein oscillator treatment is filled by transforming the phonon Hamiltonian back to the particle variables. The particle-coordinate, normalized, wave function for the phonon vacuum state is exhibited.

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PubMed1990

Phonon dynamics.

An atomic lattice in its ground state is excited by the rapid displacement and release of an atomic constituent. The time dependence of the energy transfer to other constituents is studied by using a phonon dispersion relation that is linear in frequency and propagation vector components.

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