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Theory of Quantized Fields III.

DE20054368814

Publication Date	2005
Personal Author	Schwinger, J.
Page Count	40
Abstract	In this paper we discuss the electromagnetic field, as perturbed by a prescribed current. All quantities of physical interest in various situations, eigenvalues, eigenfunctions, and transition probabilities, are derived from a general transformation function which is expressed in a non-Hermitian representation. The problems treated are: the determination of the energy-momentum eigenvalues and eigenfunctions for the isolated electromagnetic field, and the energy eigenvalues and eigenfunctions for the field perturbed by a time-independent current; the evaluation of transition probabilities and photon number expectation values for a time-dependent current that departs from zero only within a finite time interval, and for a time-dependent current that assumes non-vanishing time-independent values initially and finally. The results are applied in a discussion of the infrared catastrophe and of the adiabatic theorem. It is shown how the latter can be exploited to give a uniform formulation for all problems requiring the evaluation of transition probabilities or eigenvalue displacements.
Keywords	Electromagnetic fields Currents Eigenvalues Eigenfunctions Energy Transition probabilities Photons Time dependence Transformations Expectation value Quantum mechanics Quantum electrodynamics
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Harvard Univ., Cambridge, MA.; Department of Energy, Washington, DC.
Supplemental Notes	Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200601

Theory of Quantized Fields III.

Theory of Quantized Fields III.
DE20054368814

Publication Date	2005
Personal Author	Schwinger, J.
Page Count	40
Abstract	In this paper we discuss the electromagnetic field, as perturbed by a prescribed current. All quantities of physical interest in various situations, eigenvalues, eigenfunctions, and transition probabilities, are derived from a general transformation function which is expressed in a non-Hermitian representation. The problems treated are: the determination of the energy-momentum eigenvalues and eigenfunctions for the isolated electromagnetic field, and the energy eigenvalues and eigenfunctions for the field perturbed by a time-independent current; the evaluation of transition probabilities and photon number expectation values for a time-dependent current that departs from zero only within a finite time interval, and for a time-dependent current that assumes non-vanishing time-independent values initially and finally. The results are applied in a discussion of the infrared catastrophe and of the adiabatic theorem. It is shown how the latter can be exploited to give a uniform formulation for all problems requiring the evaluation of transition probabilities or eigenvalue displacements.
Keywords	Electromagnetic fields Currents Eigenvalues Eigenfunctions Energy Transition probabilities Photons Time dependence Transformations Expectation value Quantum mechanics Quantum electrodynamics
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Harvard Univ., Cambridge, MA.; Department of Energy, Washington, DC.
Supplemental Notes	Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200601