How to Squeeze the Vacuum, Or, What to Do When Even No Quantum Is Half a Quantum Too Many

Abstract

The vacuum is conventionally defined as the absence of matter and energy. One might imagine that such a vacuum would be simple and without interest to physicists. Quantum mechanics, however, provides a detailed and complex model of the vacuum, pregnant with possibilities and well worth careful study [1], The quantum mechanical vacuum is defined as the ground state of all fields. The electromagnetic field is the field most familiar to spectroscopists, and is the model used to understand more complex forces. The electromagnetic field is conventionally modelled as an assembly of harmonic oscillator modes. It is well known that the ground state of a harmonic oscillator does not have zero energy; instead, it contains one half quantum. This vacuum energy allows an oscillator in the ground state to have a slightly fluctuating position and momentum and thus fulfil the uncertainty principle [2].