Squeezed quantum states of relic gravitons and primordial density fluctuations

Abstract

The close relationship between the theory of particle creation in external fields and the theory of quantum-mechanical squeezed states is clarified. It is shown that relic gravitons (and other primordial perturbations), created from zero-point quantum fluctuations in the course of cosmological evolution, should now be in strongly squeezed states. The statistical properties of the stochastic collection of relic gravitational waves are investigated. Some other examples of particle creation, and in particular Hawking's process of black-hole evaporation, are considered in the context of the theory of squeezed states.