Cosmology of multigravity
We have constructed a nonlinear multi-graviton theory. An application of this theory to cosmology is discussed. We found that scale factors in a solution for this theory repeat acceleration and deceleration.
gr-qc↗
arXiv subjects
Kiyoshi Shiraishi
Publications and source records attributed to Kiyoshi Shiraishi.
Cancellation of long-range forces in Einstein-Maxwell-dilaton system
We examine cancellation of long-range forces in Einstein-Maxwell-Dilatonic system. Several conditions of the equilibrium of two charged masses in general relativity is found by many authors. These conditions are altered by taking account of dilatonic field. Under the new condition, we show cancellation of $1/r^2$ potential using Feynman diagrams.
hep-th↗
Emergent Einstein Universe under Deconstruction
We study self-consistent static solutions for an Einstein universe in a graph-based induced gravity. The one-loop quantum action is computed at finite temperature. In particular, we demonstrate specific results for the models based on cycle graphs.
gr-qc↗
Multi-graviton theory in vierbein formalism
Recently, multi-graviton theory on a simple closed circuit graph corresponding to the $S^1$ compactification of the Kaluza-Klein (KK) theory has been considered. In the present paper, we extend this theory to that on a general graph and study what modes of particles are included. Furthermore, we generalize it in a possible non-linear theory based on the vierbein formalism and study cosmological solutions.
gr-qc↗
Induced Gravity in Deconstructed Space at Finite Temperature -- Self-consistent Einstein Universe
We study self-consistent cosmological solutions for an Einstein Universe in a graph-based induced gravity model. The graph-based field theory has been proposed by the present authors to generalize dimensional deconstruction. In this paper, we consider self-consistent Einstein equations for a ``graph theory space''. Especially, we demonstrate specific results for cycle graphs.
gr-qc↗
Divergences in QED on a Graph
We consider a model of quantum electrodynamics (QED) on a graph. The one-loop divergences in the model are investigated by use of the background field method.
hep-th↗
Finite density effects in Hosotani mechanism and a vacuum gauge ball
We consider the finite density effects of the fermion with U(1) gauge symmetry in Hosotani mechanism. We construct a vacuum gauge ball, a new kind of non-topological soliton, and investigate their properties numerically. We find the relations between the physical quantities.
hep-ph↗
One-loop effective potential for the vacuum gauge field in $M_3\times S^3 \times S^1$ space-times
We calculate the effective potential for the vacuum gauge field from the one-loop matter effect in $M_3\times S^3\times S^1$ space-time. This background geometry is motivated from the recent studies on gauged supergravities with a positive-definite potential, which admits a generalized Kaluza-Klein reduction. We investigate how symmetry breaking patterns through the Hosotani mechanism are affected by the ratio of the radii of $S^1$ and $S^3$.
hep-th↗
Non-topological soliton in three-dimensional supergravity
We construct numerical solutions for non-topological solitons in three-dimensional U(1)-gauged ${\cal N}=2$ supergravity. We find the region of the solutions showing with the BTZ mass, the angular momentum and the magnetic flux and discuss the relation among the physical parameters for various values of a cosmological constant.
gr-qc↗
Induced Gravity from Theory Space
The mass spectrum of a model constructed in a theory space is expressed by eigenvalues of the Laplacian on the graph structure of the theory space. The nature of the one-loop UV divergence in the vacuum energy is then controlled only by the degree matrix of the graph. Using these facts, we can construct models of induced gravity which do not suffer from divergences at the one-loop level.
gr-qc↗
One-loop finite potential for N-2 scalars from N quantum fields
We study the one-loop effective potential induced from quantum fluctuation of a finite number of fields. A series expansion in terms of the modified Bessel functions is useful to evaluate the one-loop effective potential. We find that at most $N-2$ scalars parameterize the one-loop finite potential and the explicit parameterization is shown. The structure of the potential for N=4 is investigated as the simplest case. The implication of the model is discussed.
hep-ph↗
Compactification in deconstructed gauge theory with topologically non-trivial link fields
We investigate the mass spectrum of a scalar field in a world with latticized and circular continuum space where background fields takes a topological configuration. We find that the mass spectrum is related to the characteristic values of Mathieu functions. The gauge symmetry breaking in a similar spacetime is also discussed.
hep-th↗
Quantum Scattering in Two Black Hole Moduli Space
We discuss the quantum scattering process in the moduli space consisting of two maximally charged dilaton black holes. The black hole moduli space geometry has different structures for arbitrary dimensions and various values of dilaton coupling. We study the quantum effects of the different moduli space geometries with scattering process. Then, it is found that there is a resonance state on certain moduli spaces.
gr-qc↗
Multi-graviton theory, a latticized dimension, and the cosmological constant
Beginning with the Pauli-Fierz theory, we construct a model for multi-graviton theory. Couplings between gravitons belonging to nearest-neighbor ``theory spaces'' lead to a discrete mass spectrum. Our model coincides with the Kaluza-Klein theory whose fifth dimension is latticized. We evaluate one-loop vacuum energy in models with a circular latticized extra dimension as well as with compact continuous dimensions. We find that the vacuum energy can take a positive value, if the dimension of the continuous space time is $6, 10,...$. Moreover, since the amount of the vacuum energy can be an arbitrary small value according to the choice of parameters in the model, our models is useful to explain the small positive dark energy in the present universe.
gr-qc↗
Shape of Deconstruction
We construct a six-dimensional Maxwell theory using a latticized extra space, the continuum limit of which is a shifted torus recently discussed by Dienes. This toy model exhibits the correspondence between continuum theory and discrete theory, and give a geometrical insight to theory-space model building.
hep-ph↗
Deconstructing Scalar QED at Zero and Finite Temperature
We calculate the effective potential for the WLPNGB in a world with a circular latticized extra dimension. The mass of the WLPNGB is calculated from the one-loop quantum effect of scalar fields at zero and finite temperature. We show that a series expansion by the modified Bessel functions is useful to calculate the one-loop effective potentials.
hep-th↗
Bulk Fermion Stars with New Dimensions
Many efforts have been devoted to the studies of the phenomenology in particle physics with extra dimensions. We propose degenerate fermion stars with extra dimensions and study what features characterized by the size of extra dimensions should appear in its structure. We find that Kaluza-Klein excited modes arise for the larger scale of extra dimensions and examine the conditions on which different layers should be caused in the inside of the stars. We expound how the extra dimensions affect on physical quantities.
gr-qc↗
Noncommutative gravity in three dimensions coupled to spinning sources
Noncommutative gravity in three dimensions with vanishing cosmological constant is examined. We find a solution which describes a spacetime in the presence of a torsional source. We estimate the phase shift for each partial wave of a scalar field in the spacetime by the Born approximation.
hep-th↗