Quantum Birth of a Hot Universe II. Model Parameter Estimates from CMB Temperature Fluctuations

TL;DR

This paper models the quantum origin of a hot universe considering vacuum fluctuations with radiation and strings, estimating parameters from CMB temperature fluctuations and linking them to early universe theories.

Contribution

It introduces a quantum cosmological model incorporating strings and radiation, providing parameter estimates based on CMB data and exploring conditions for universe nucleation.

Findings

Temperature spectrum consistent with CMB constraints

Lower temperature limit aligns with reheating predictions

Upper temperature limit exceeds monopole mass threshold

Abstract

We consider the quantum birth of a hot FRW universe from a vacuum-dominated quantum fluctuation with admixture of radiation and strings, which correspond to quantum tunnelling from a discrete energy level with a non-zero temperature. The presence of strings with the equation of state $p=-\epsilon/3$ mimics a positive curvature term which makes it possible, in the case of a negative deficit angle, the quantum birth of an open and flat universe. In the pre-de-Sitter domain radiation energy levels are quantized. We calculate the temperature spectrum and estimate the range of the model parameters restricting temperature fluctuations by the observational constraint on the CMB anisotropy. For the GUT scale of initial de Sitter vacuum the lower limit on the temperature at the start of classical evolution is close to the values as predicted by reheating theories, while the upper limit is far from the threshold for a monopole rest mass.