Decoherence in Pre-Big-Bang Cosmology

TL;DR

This paper investigates quantum decoherence in a simple pre-big-bang cosmological model, analyzing how inhomogeneous dilaton fluctuations affect the transition from quantum to classical behavior and implications for cosmological evolution.

Contribution

It introduces a framework for including inhomogeneous dilaton fluctuations in pre-big-bang quantum cosmology and examines their impact on decoherence and the exit problem.

Findings

Decoherence can be achieved by choosing specific vacua.

Generically, decoherence is expected in the model.

Results have implications for the exit problem in pre-big-bang cosmology.

Abstract

We analyze the quantum cosmology of the simplest pre--big--bang model without dilaton potential. In addition to the minisuperspace variables we include inhomogeneous dilaton fluctuations and determine their wave function on a semiclassical background. This wave function is used to calculate the reduced density matrix and to find criteria for the loss of decoherence. It is shown that coherence between different backgrounds can always be achieved by a specific choice of vacua though generically decoherence can be expected. In particular, we discuss the implications of these results on the ``exit problem'' of pre--big--bang cosmology.