arXiv subjects

P K Suresh

Publications and source records attributed to P K Suresh.

16 recordsLinked to original sources

arXiv2026

Yukawa coupling and one loop inflation in the light of CMB

The one loop inflation stemming from the superstring theory and associated Yukawa coupling arising from supersymmetric interactions is examined with CMB. The Yukawa coupling can exist beyond standard model particle physics sector. The tensor-to-scalar ratio of the loop inflation is found consistent with the recent CMB results for the Yukawa coupling from cosmology. The alternative constraint on the Yukawa coupling from loop inflation may play a crucial role in validating inflationary model originating from supersymmetry and string theory. The outcomes of the study may be helpful in the phenomenological realisation of string theory.

physics.gen-ph↗

arXiv2025

Unraveling the Hubble tension with warm inflation

The validity of warm inflation is investigated in the light of recent CMB missions in both strong and weak dissipative regimes. The tensor to scalar ratio of various inflationary models is found to be consistent with the recent CMB results for different models of warm inflation. The role of dissipation on the popular models of warm inflation in the context of supersymmetry and string theory is investigated. Further, the effect of dissipation coefficient of warm inflation on the Hubble parameter and its role in accounting the Hubble tension is examined. Warm inflation embodies superstring theory and can provide a platform to test quantum gravity in multi field scenario.

gr-qc↗

arXiv2024

A possible solution to the Hubble tension from quantum gravity

We investigate the relevance of quantum gravity during inflation to address the Hubble tension that arises from Planck 2018 and SH0ES data sets. We show that the effect of quantum gravity during inflation can increase the rate of change of $H_0$, thereby accounting for a wide range of observed $H_0$. Further, we show that due to the quantum gravity effect on inflation, the temperature at the onset of reheating can be lower than the standard case, causing delays in the reheating process. The role of quantum gravity is inevitable in settling the Hubble tension. The results of the present study may find use in resolving the Hubble tension, in validating inflationary model and quantum gravity.

gr-qc↗

arXiv2023

A Unique Approach to Classify Inflationary Potentials

Inflationary cosmology has made significant strides in understanding the physics driving the rapid expansion of the early universe. However, many inflation models with diverse potential shapes present analysis, comparison, and classification challenges. In this paper, we propose a novel approach to tackle this issue. We introduce a general potential formula encompassing all inflationary potentials, whether single-field or multi-field, into a single mathematical framework. This formula establishes a unified framework for systematically classifying inflation models based on their potential functions. We showcase the efficacy of the general potential formula by successfully reproducing well-known inflation models, such as the Starobinsky potential and the Valley Hybrid Inflation model. Moreover, we derive general inflationary parameters, including the slow-roll parameters and power spectra, using the proposed formula. Our approach provides a versatile tool for classifying and studying various inflationary scenarios, simplifying the analysis and comparison of different models in the field of inflationary cosmology.

astro-ph.CO↗

arXiv2022

Oscillatory amplitude of stochastic gravitational wave spectrum

Primordial gravitational waves generated from early universe are placed in the squeezed vacuum state and the resulting stochastic background is studied for various models of the expanding universe. The quantum effect on the stochastic gravitational waves leads to overall enhancement of the amplitude and spectral energy density when compared to those in the absence of squeezing effect with continued increase in the amplitude in the accelerating stage and oscillatory behavior at higher frequency range of the spectrum in the accelerating universe. Through the quantum effect, it is also found that the reheating phenomenon affects the entire spectrum. The results of the present study may be useful to test the possibility of detection of the stochastic gravitational waves by current and future gravitational wave detectors and whether these waves exist in the squeezed vacuum state.

gr-qc↗

arXiv2021

Curvaton and quantum gravity effect on the tensor to scalar ratio of the chaotic inflation

The expected tensor-to-scalar ratio estimate of the upcoming CMB mission probe measurements may establish a lower value of the ratio than the currently obtained value. It can be described in terms of a single field chaotic inflation model along with the curvaton or quantum gravity or their combined effect. Consequently, the role of quantum gravity or curvaton in the dynamics of the early universe may not be ruled out. The curvaton scenario and quantum gravity effect can be tested experimentally.

gr-qc↗

arXiv2020

Bouncing Universe with exotic radiation

Scenario bouncing can give the cosmology singularity problem a possible way out. Finding a solution for the universe's bouncing model requires proper estimation of the state equation. We present two such state equations that give us the solution for a bounce. One such case is the exotic radiation, where we assumed that exotic radiation dominated the universe during the bounce occurrence. We also considered another case where quintom matter scenario existed previously, and the newly proposed exotic radiation scenario coexisted. In these two cases, we have shown that all the necessary conditions for the bounce are fulfilled. Such new ways certainly increase support and flexibility for the bouncing universe model.

gr-qc↗

arXiv2014

Spherically Symmetric Solution in Bi-metric theory of Gravity

The possibility of spherically symmetric solutions in bi-metric theory of gravity is examined. It is shown that two possible black hole type solutions exists in the model. Spherically symmetric solution of general theory of relativity is recovered in the absence of the second metric. The result is compared with other bi-metric models as well as general theory of relativity.

gr-qc↗

arXiv2012

Modified Amplitude of Gravitational Waves Spectrum

The spectrum of thermal gravitational waves is obtained by including the high frequency thermal gravitons created from extra-dimensional effect and is a new feature of the spectrum. The amplitude and spectral energy density of gravitational waves in thermal vacuum state are found enhanced. The amplitude of the waves get modified in the frequency range (10$^{-16}$ -10 $^{8}$ Hz) but the corresponding spectral energy density is less than the upper bound of various estimated results. With the addition of higher frequency thermal waves, the obtained spectral energy density of the wave in thermal vacuum state does not exceed the upper bound put by nucleosynthesis rate. The existence of cosmologically originated thermal gravitational waves due to extra dimension is not ruled out.

gr-qc↗

arXiv2008

Dvali-Gabadadze-Porrati Cosmology in Bianchi I brane

The dynamics of Dvali-Gabadadze-Porrati Cosmology (DGP) braneworld with an anisotropic brane is studied. The Friedmann equations and their solutions are obtained for two branches of anisotropic DGP model. The late time behavior in DGP cosmology is examined in the presence of anisotropy which shows that universe enters a self-accelerating phase much later compared to the isotropic case. The acceleration conditions and slow-roll conditions for inflation are obtained.

gr-qc↗

arXiv2007

On the one-loop correction of "phi^4" theory in higher dimensions

We have considered phi^4 theory in higher dimensions. Using functional diagrammatic approach, we computed the one-loop correction to effective potential of the scalar field in five dimensions. It is shown that phi^4 theory can be regularised in five dimensions. Temperature dependent one-loop correction and critical temperature T_c are computed and T_c depends on the fundamental scale M of the theory. A brief discussion of symmetry restoration is also presented. The nature of phase transitions is examined and is of second order

hep-th↗

arXiv2006

Gravity and Large Extra Dimensions

The idea that quantum gravity can be realized at the TeV scale is extremely attractive to theorists and experimentalists alike. This proposal leads to extra spacial dimensions large compared to the electroweak scale. Here we give a very systematic view of the foundations of the theories with large extra dimensions and their physical consequences.

hep-th↗

arXiv2006

Gravitons in Kaluza-Klein Theory

This is a pedagogical introduction to original Kaluza-Klein theory and its salient features. Most of the technical calculations are given in detail and the nature of gravitons is discussed.

gr-qc↗

arXiv2005

Are We Living in a Higher Dimensional Universe?

It is a brief review of the physical theories embodying the idea of extra dimensions, starting from the pre-historic times to the present day. Here we have classified the developments into three eras, such as Pre-Einstein, Einstein and Kaluza-Klein. Here the views and flow of thoughts are emphasized rather rigorous mathematical details. Majour developments in Quantum field theory and Particle physics are outlined. Some well known higher dimensional approaches to unification are discussed. This is concluded with some examples for visualizing extra dimensions and a short discussion on the cosmological implications and possible existence of the same.

gr-qc↗

arXiv2005

Supernovae: Explosions in the Cosmos

In this article, a broad perspective of supernovae, their classification and mechanism is given. Later, the astrophysical significance of supernovae is discussed in brief.

astro-ph↗

arXiv2004

Finite temperature effects in brane cosmology

Finite temperature effects in brane world cosmology are studied by considering the interaction between scalar field and bulk gravity. One-loop correction to zero-temperature potential is computed by taking into account, interaction of scalar field and bulk gravity. Phase transitions and high temperature symmetry restoration are examined. Critical temperature of phase transitions depends on the interaction constant of the scalar field and bulk gravity, and these constant is an order parameter. Present study can account for second order phase transition in early universe, in brane world cosmological scenario.

gr-qc↗