arXiv subjects

Anupama B

Publications and source records attributed to Anupama B.

5 recordsLinked to original sources

arXiv2025

Role of dynamical early dark energy in Hubble tension through warm inflation

The role of dissipation from the thermal bath of minimal warm inflation (MWI)is examined with the Cosmic Microwave Background (CMB) to assess its ability to mimic a dynamical dark energy component. An increase in the dissipation strength modifies temperature anisotropies and shifts the phase and peak structure of the CMB TT angular power spectrum in a manner analogous to evolving dark energy. Bayesian parameter estimation for cosmological parameters of MWI using Markov Chain Monte Carlo analysis with Planck18 + BICEP/Keck 2018 + sn.pantheon + SH0ES likelihoods reveals deviations from standard $\Lambda$CDM constraints, accompanied by an enhancement in the matter power spectrum that signals possible physics beyond the conventional model. Notably, the present day Hubble parameter increases with dissipation strength, indicating that minimal warm inflation can naturally generate a dynamical early dark energy like behavior capable of alleviating the Hubble tension. Within this unified framework, early and late time estimates of $H_0$ can be reconciled. Further, the time varying dark energy equation of state consistent with recent DESI DR2 indication favours a quantum gravity phase preceding the inflationary epoch.

gr-qc↗

arXiv2025

Thermal gravitational waves from warm inflation

For the first time, the possibility of generation of thermal gravitational waves from warm inflation is investigated with cosmic microwave background. Gravitons produced from the quantum fluctuations during warm inflation are found to carry the thermal features if they exist in a thermal squeezed vacuum state. Thermal squeezing reduces the amplitude of the BB mode angular power spectrum of CMB when compared with the conventional cold inflation. This work inspects the thermal nature of tensor power spectrum from warm inflation and the relevance of quantum fluctuations over the thermal fluctuations. The dust corrected lensed BB modes from joint analysis of $Planck$ and BICEP2/$Keck$ for warm inflation provide compelling evidence for the existence of thermal gravitons.

gr-qc↗

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

Feasibility of 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 newly derived constraint on the Yukawa coupling constant may play a crucial role in validating inflationary model originating from supersymmetry and may shed some light on the formation of dark matter or dark energy. The outcomes of the study may be helpful in the phenomenological realisation of string theory.

physics.gen-ph↗

arXiv2023

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↗