Gauge-noninvariance of quantum cosmology and vacuum dark energy

We address the question how to adapt cosmological constant $\Lambda$ for description of a vacuum dark energy density jumping from the big initial value to the small today value suggested by observations. We find such a possibility in the gauge-noninvariance of quantum cosmology which leads to a connection between a choice of the gauge and quantum spectrum for a certain physical quantity which can be specified in the framework of the minisuperspace model. We introduce a particular gauge in which the cosmological constant $\Lambda$ is quantized and show that making a measurement of $\Lambda$ today one can find its small value with the biggest probability, while at the beginning of the evolution, the biggest probability corresponds to its biggest value. Transitions between quantum levels of $\Lambda$ in the course of the Universe evolution, could be related to several scales for symmetry breaking.Comment: 5 pages, 1 figur

Quantum birth of a hot universe

AbstractWe consider the quantum birth of a hot FRW universe from a vacuum-dominated quantum fluctuation with admixture of radiation and strings which corresponds to quantum tunnelling from a discrete energy level with a non-zero temperature. The presence of strings with the equation of state p=−ε/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 a 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 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