arXiv:quant-ph/9506025 · Fortschritte der Physik/Progress of Physics
Holstein-Primakoff/Bogoliubov Transformations and the Multiboson System
Michael Martin Nieto, D. Rodney Truax
Abstract
As an aid to understanding the displacement operator definition of squeezed states for arbitrary systems, we investigate the properties of systems where there is a Holstein-Primakoff or Bogoliubov transformation. In these cases the ladder-operator or minimum-uncertainty definitions of squeezed states are equivalent to an extent displacement-operator definition. We exemplify this in a setting where there are operators satisfying [A, Aå] = 1, but the A's are not necessarily the Fock space a's; the multiboson system. It has been previously observed that the ground state of a system often can be shown to to be a coherent state. We demonstrate why this must be so. We close with a discussion of an alternative, effective definition of displacement-operator squeezed states.