arXiv subjects

B. S. Balakrishna

Publications and source records attributed to B. S. Balakrishna.

8 recordsLinked to original sources

arXiv2023

Solvable potentials in a FLRW+Scalar universe and Fits to type Ia supernovae data

FLRW equations are analyzed in a universe with a cosmic scalar background that is spatially uniform but time-varying. Some solvable potentials to the combined dynamics in such a universe are presented, that are consistent with the scalar dynamics as a consequence of energy momentum conservation. Certain potentials are found to provide very good fits to type Ia supernovae data, with the kinetic and potential energies of the scalar providing the source for dark matter and dark energy. The scalar rolls down the potential as the universe expands with the potential playing the role of a time-varying cosmological constant, modeling a scenario recently discussed in the literature.

gr-qc↗

arXiv2023

From Cosmic Inflation and Matter Creation to Dark Matter -- Journey of the Inflaton?

A scenario of the inflaton evolution from cosmic inflation and matter creation to dark matter/dark energy today is presented. To start with, a model of the inflationary phase of the inflaton is introduced. The inflaton rolls down a hilltop potential along with matter creation being dragged down by the presence of matter. Presence of matter provides a mechanism to stop universe's acceleration and hence the inflationary phase. The model predictions for the standard metrics are fully consistent with the current CMB limits. The potential could in principle be extended to complete a potential hill subsequent to inflation. The evolution of the inflaton from the inflationary phase to radiation/matter dominated eras and to current times can be inferred qualitatively following the evolution of its equation of state parameter. Existence of solutions to its dynamics, tracking matter as it evolves to current times, provides a plausible reasoning for the relative order of magnitudes of the cosmological parameters, in particular to the relative abundance of dark matter today.

hep-ph↗

arXiv1995

Composite Gauge fields and Broken Symmetries

A generalization of the non-Abelian version of the $CP^{N-1}$ models (also known as Grassmannian models) is presented. The generalization helps accommodate a partial breaking of the non-Abelian gauge symmetry. Constituents of the composite gauge fields, in many cases, are naturally constrained to belong to an anomaly free representation which in turn generates a composite scalar simulating Higgs mechanism to break the gauge symmetry dynamically for large $N$. Two cases are studied in detail: one based on the SU(2) gauge group and the other on SO(10). Breakings such as SU(2)$\to$U(1) or SO(10)$\to$SU(5)$\times$U(1) are found feasible. Properties of the composites fields and gauge boson masses are computed by doing a derivative expansion of the large $N$ effective action.

hep-th↗

arXiv1993

Composite gauge field models with broken symmetries

We present a generalization of the non-Abelian version of the $CP^{N-1}$ models (also known as Grassmannian models) that involve composite gauge fields to accommodate partial breaking of the non-Abelian gauge symmetry. For this to be possible, in most cases, the constituent fields need to belong to an anomaly free complex representation. Symmetry is broken dynamically for large $N$ primarily by a naturally generated composite scalar which simulates Higgs mechanism. In the example studied in some detail, the gauge group SO(10) gets broken down to subgroups like SU(5) or SU(5)$\times$U(1).

hep-th↗

arXiv1993

Anomaly matching for the QCD string

A criterion to be satisfied by a string theory of QCD is formulated in the ultraviolet regime. It arises from the trace anomaly of the QCD stress tensor computed using instantons. It is sensitive to asymptotic freedom. It appears to be related to the trace anomaly of the QCD string. Our current understanding of noncritical strings in physical dimensions is limited, but remarkably, a formal treatment of the bosonic string yields numerical agreement both in magnitude and sign for the gauge group SU(2).

hep-th↗

arXiv1993

Difficulties in Inducing a Gauge Theory at Large N

It is argued that the recently proposed Kazakov-Migdal model of induced gauge theory, at large $N$, involves only the zero area Wilson loops that are effectively trees in the gauge action induced by the scalars. This retains only a constant part of the gauge action excluding plaquettes or anything like them and the gauge variables drop out.

hep-th↗

arXiv1992

Double Scaling Limit of Scalar Theories on the Lattice

Scalar field theories regularized on a $D$ dimensional lattice are found to exhibit double scaling for a class of critical behaviors labeled by an integer $m\geq 2$. The continuum theory reached in the double scaling limit defines a universality class and is of a massless scalar with only a $m+1$ point self-interaction, but in the presence of a constant source. The upper critical dimension for this to occur is the same as that for renormalizability of the $m+1$ point interaction.

hep-th↗

arXiv1992

Non-Abelian Monopoles Coupled to Gravity

A static configuration of point charges held together by the gravitational attraction is known to be given by the Majumdar-Papapetrou solution in the Einstein-Maxwell theory. We consider a generalization of this solution to non-Abelian monopoles of the Yang-Mills Higgs system coupled to gravity. The solution is governed by an analog of the Bogomol'nyi equations that had played a central role in the analysis of non-Abelian monopoles.

hep-th↗