Fields and Quanta

Abstract

By means of plausible arguments based on physical reasoning, single particle quantum mechanics is extended to the quantization of fields. Field operators and a field Hamiltonian are introduced. Special consideration is devoted to the particle picture as an excitation of the quantum field and its consequences for the counterintuitive non-locality in quantum physics. The formalism of field quantization is applied to the electromagnetic field, the many-body field of non-relativistic particles as well as to the lattice wave (phonon) field in crystals. As application examples for the quantized electromagnetic field the following issues are discussed: the influence of “Which Way” information on quantum interferences, the Casimir effect and the spontaneous emission of light quanta. In connection with particle and phonon fields, electrons in solids as well as phonon–phonon and phonon–electron interaction are considered. Phonon–electron interaction is used as a paradigm to explain the general quantum field theoretical concept of particle interaction via exchange of field quanta.