Comparison of quantum and semiclassical radiation theories with application to the beam maser

  title={Comparison of quantum and semiclassical radiation theories with application to the beam maser},
  author={Edwin T. Jaynes and Frederick W. Cummings},
This paper has two purposes: 1) to clarify the relationship between the quantum theory of radiation, where the electromagnetic field-expansion coefficients satisfy commutation relations, and the semiclassical theory, where the electromagnetic field is considered as a definite function of time rather than as an operator; and 2) to apply some of the results in a study of amplitude and frequency stability in a molecular beam maser. In 1), it is shown that the semiclassical theory, when extended te… 

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