2 research outputs found
Dust reference frame in quantum cosmology
We give a formulation of quantum cosmology with a pressureless dust and
arbitrary additional matter fields. The system has the property that its
Hamiltonian constraint is linear in the dust momentum. This feature provides a
natural time gauge, leading to a physical hamiltonian that is not a square
root. Quantization leads to Schr{\"o}dinger equation for which unitary
evolution is directly linked to geodesic completeness. Our approach simplifies
the analysis of both Wheeler-deWitt and loop quantum cosmology (LQC) models,
and significantly broadens the applicability of the latter. This is
demonstrated for arbitrary scalar field potential and cosmological constant in
LQC.Comment: 8 pages, iopart style + BibTe
Inflation from non-minimally coupled scalar field in loop quantum cosmology
The FRW model with non-minimally coupled massive scalar field has been
investigated in LQC framework. Considered form of the potential and coupling
allows applications to Higgs driven inflation. Out of two frames used in the
literature to describe such systems: Jordan and Einstein frame, the latter one
is applied. Specifically, we explore the idea of the Einstein frame being the
natural 'environment' for quantization and the Jordan picture having an
emergent nature. The resulting dynamics qualitatively modifies the standard
bounce paradigm in LQC in two ways: (i) the bounce point is no longer marked by
critical matter energy density, (ii) the Planck scale physics features the
'mexican hat' trajectory with two consecutive bounces and rapid expansion and
recollapse between them. Furthermore, for physically viable coupling strength
and initial data the subsequent inflation exceeds 60 e-foldings.Comment: Clarity improved. Replaced with revised version accepted in JCA