Recently the mechanism was found which allows avoidance of the cosmological singularity within the semi-classical formulation of Loop Quantum Gravity. Numerical studies show that the presence of self-interaction potential of the scalar field allows generation of initial conditions for successful slow-roll inflation. In this paper qualitative analysis of dynamical system, corresponding to cosmol...

We study the influence of the shape of compact dimensions to the Casimir energy and Casimir force of a scalar field. We examine both the massive and the massless scalar field. The total spacetime topology is M D ×T 2 θ , where M D is the D dimensional Minkowski spacetime and T 2 θ the twisted torus described by R 1 , R 2 and θ. For the case R 1 = R 2 we found that the massive bulk scalar field ...

We consider the thermodynamics of minimally coupled massive scalar field in 3+1 dimensional Taub-NUT background. The brick wall model of 't Hooft is used. A quantization condition on the energy of the matter field, similar to the Dirac quantization condition, is required to find well behaved solution of the scalar field wave equation.When Scharzschild like coordinates are used it is found that ...

Vacuum expectation values (VEVs) of the current densities for charged scalar and Dirac spinor fields are investigated in (D+1)-dimensional de Sitter (dS) spacetime with toroidally compactified spatial dimensions. Along compact dimensions we impose quasiperiodicity conditions with arbitrary phases. In addition, the presence of a classical constant gauge field is assumed. The VEVs of the charge d...

Using the manifestly spacetime-supersymmetric version of open superstring field theory , we construct the free action for the first massive states of the open superstring com-pactified to four dimensions. This action is in N=1 D=4 superspace and describes a massive spin-2 multiplet coupled to two massive scalar multiplets.

It is shown that there exists a range of parameters in which gravitational collapse with a spherically symmetric massive scalar field can be treated as if it were collapsing dust. This implies a criterion for the formation of black holes depending on the size and mass of the initial field configuration and the mass of the scalar field. Pacs numbers: 03.70.+k, 98.80.Cq Typeset using REVTEX

A gauge invariant formulation for the massive axion is considered. The axion acquires mass through a topological term which couples a (pseudo)scalar and a third rank antisymmetric tensor. Duality, local and canonical equivalences with the non-gauge invariant proposal are established. The supersymmetric version of the gauge invariant model is constructed. It is well known that different theories...

We show, using the large N limit, that there is a non–trivial scale invariant action for four dimensional scalar field theory. We investigate the possibility that the scalar sector of the standard model of particle physics has such a scale invariant action, with scale invariance being spontaneously broken by the vacuum expectation value of the scalar. This leads to a prediction for the mass of ...

We investigate whether interaction between massive neutrinos and quintessence scalar field is the origin of the late time accelerated expansion of the universe. We present explicit formulas of the cosmological linear perturbation theory in the neutrinos probes of dark-energy model, and calculate cosmic microwave background anisotropies and matter power spectra. In these models, the evolution of...

The vacuum expectation value of the stress-energy tensor 〈0 |Tμν | 0〉 is calculated in several multiply connected flat spacetimes for a massive scalar field with arbitrary curvature coupling. We find that a nonzero field mass always decreases the magnitude of the energy density in chronology-respecting manifolds such as R3×S1, R2×T 2, R1×T 3, the Möbius strip, and the Klein bottle. In Grant spa...