Gauge-noninvariance of quantum cosmology and vacuum dark energy

We address the question how to adapt cosmological constant Λ 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 Λ is quantized and show that making a measurement of Λ 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 Λ in the course of the Universe evolution, could be related to several scales for symmetry breaking. © 2006 Elsevier B.V. All rights reserved.