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Radiation and Quantum Electrodynamics

  • Hartmut M. Pilkuhn
Part of the Texts and Monographs in Physics book series (TMP)

Abstract

So far in this book the 4-potential A μ (t, x) was either classical or due to a nucleus. An essential extension of the formalism is necessary for processes in which photons are emitted or absorbed. For example, if an excited atom |e i > has been formed by a rapid collision at a certain time, the probability amplitude of finding the atom in the state |e i > decreases afterwards, and new states |e f > |γ λ (k)> appear, in which the atom is in states of lower energy, the missing energy being carried away by a photon |γ λ of momentum ħ k. The Hamilton operator (1–4.2) is capable of inducing such transitions, but only if A μ is interpreted as an operator which can create and annihilate photons. As explained in section 2–8, gauge invariance permits us to impose the condition div A = 0 on this operator. Since we wish to keep classical electric and magnetic fields as well, we put
$$ {A^\mu }(x) = A_{cl}^\mu (x) + A_{op}^\mu (x),A_{op}^0 = 0,div{A_{op}} = 0 $$
.

Keywords

Matrix Element Pair Production Differential Cross Section Gauge Invariance Quantum Electrodynamic 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag Berlin Heidelberg 1979

Authors and Affiliations

  • Hartmut M. Pilkuhn
    • 1
  1. 1.Institut für KernphysikUniversität KarlsruheFederal Republic of Germany

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