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Behrooz Malekolkalami

Academic rank: Associate Professor
ORCID:
Education: PhD.
ScopusId: 654654
Faculty: Faculty of Science
Address:
Phone: 09188711601

Research

Title
Noncommutative Double Scalar Fields in FRW Cosmology as Cosmical Oscillators
Type
JournalPaper
Keywords
Noncommutative Phase Space; Double Scalar Field Cosmology; Quantum Cosmology; Noether Symmetry; Scalar–Tensor Theory.
Year
2010
Journal Classical and Quantum Gravity
DOI
Researchers Behrooz Malekolkalami ، Mehrdad FARHOUDI

Abstract

We investigate the effects caused by noncommutativity of the phase space generated by two scalar fields that have non-minimal conformal couplings to the background curvature in the FRW cosmology. We restrict deformation of the minisuperspace to noncommutativity between the scalar fields and between their canonical conjugate momenta. Then, the investigation is carried out by means of a comparative analysis of the mathematical properties (supplemented with some diagrams) of the time evolution of variables in a classical model and the wavefunction of the universe in a quantum perspective, both in the commutative and noncommutative frames. We find that the imposition of noncommutativity causes more ability in tuning time solutions of the scalar fields and, hence, has important implications in the evolution of the Universe. We find that the noncommutative parameter in the momenta sector is the only responsible parameter for the noncommutative effects in the spatially flat universes. A distinguishing feature of the noncommutative solutions of the scalar fields is that they can be simulated with the well-known three harmonic oscillators depending on three values of the spatial curvature, namely the free, forced and damped harmonic oscillators corresponding to the flat, closed and open universes, respectively. In this respect, we call them cosmical oscillators. In particular, in closed universes, when the noncommutative parameters are small, the cosmical oscillators have an analogous effect with the familiar beating effect in the sound phenomena. Some of the special solutions in the classical model and the allowedwavefunctions in the quantum model make bounds on the values of the noncommutative parameters. The existence of a non-zero constant potential (i.e. a cosmological constant) does not change time evolutions of the scalar fields, but modifies the scale factor. An interesting feature of the wellbehaved solutions of the wavefunctions is that the functional form of the r