title: Ground State of the Universe and the Cosmological Constant. A Nonperturbative Analysis.
abstract: The physical Hamiltonian of a gravity-matter system depends on the choice of time, with the vacuum naturally identified as its ground state. We study the expanding Universe with scalar field in the volume time gauge. We show that the vacuum energy density computed from the resulting Hamiltonian is a nonlinear function of the cosmological constant and time. This result provides a new perspective on the relation between time, the cosmological constant, and vacuum energy.
authors.affiliation: Department of Mathematics and Statistics, University of New Brunswick, Fredericton, New Brunswick, Canada E3B 5A3.
authors.forename: Viqar
authors.initials: V
authors.lastname: Husain
authors.affiliation: Department of Physics, LUMS School of Science and Engineering, Lahore, Pakistan.
authors.forename: Babar
authors.initials: B
authors.lastname: Qureshi