161 citations · 305 across the 14 of their papers we have counts for
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Constraining primordial non-Gaussianity and parity-violation through Scalar-Induced Gravitational Waves with next-generation ground-based interferometers
Ilaria Caporali, H. V. Ragavendra, Angelo Ricciardone +1
In this work, we investigate the prospects for probing primordial non-Gaussianity and associated symmetry of parity through scalar-induced gravitational waves (SIGWs), with third-g…
Exploring Gravitational Wave Signatures Due to Primordial Non-gaussianity and Large Scale Structure Using SKAO
H. V. Ragavendra, Giulia Capurri, Alina Mierna +8
This chapter explores theoretical and observational strategies to use the stochastic gravitational-wave background detectable by Square Kilometre Array Observatory (SKAO) as a prob…
Chiral gravitational waves from multi-phase magnetogenesis
H. V. Ragavendra, Gianmassimo Tasinato, L. Sriramkumar
Cosmological vector fields are central to many early-Universe phenomena, including inflationary dynamics, primordial magnetogenesis, and dark-matter scenarios. However, constructin…
Twisted echoes of an odd quartet: Scalar-induced gravitational waves as a probe of primordial parity-violation
H. V. Ragavendra, Nicola Bartolo
Parity-violation leaves tell-tale trails in many cosmological observables. We illustrate parity-odd primordial scalar trispectra, that despite being of modest strength, impart dete…
Scalar-induced gravitational waves from coherent initial states
Dipayan Mukherjee, H. V. Ragavendra, Shiv K. Sethi
We investigate the impact of statistical inhomogeneity and anisotropy in primordial scalar perturbations on the scalar-induced gravitational waves (SIGW). Assuming inflationary qua…
Cosmological consequences of statistical inhomogeneity
H. V. Ragavendra, Dipayan Mukherjee, Shiv K. Sethi
A space-dependent mean for cosmological perturbations negates the ansatz of statistical homogeneity and isotropy, and hence ergodicity. In this work, we construct such a primordial…
Cross-correlation between the curvature perturbations and magnetic fields in pure ultra slow roll inflation
Sagarika Tripathy, Debika Chowdhury, H. V. Ragavendra +1
Motivated by the aim of producing significant number of primordial black holes, over the past few years, there has been a considerable interest in examining models of inflation inv…
Indirect imprints of primordial non-Gaussianity on cosmic microwave background
Barnali Das, H. V. Ragavendra
Primordial non-Gaussianity arising from inflationary models is a unique probe of non-trivial dynamics of the inflaton field and its interactions with other fields. Often when exami…
Observational imprints of enhanced scalar power on small scales in ultra slow roll inflation and associated non-Gaussianities
H. V. Ragavendra, L. Sriramkumar
The discovery of gravitational waves from merging binary black holes has generated considerable interest in examining whether these black holes could have a primordial origin. If a…
Accounting for scalar non-Gaussianity in secondary gravitational waves
H. V. Ragavendra
It is well known that enhancement in the primordial scalar perturbations over small scales generates detectable amplitudes of secondary gravitational waves (GWs), by sourcing the t…
Could PBHs and secondary GWs have originated from squeezed initial states?
H. V. Ragavendra, L. Sriramkumar, Joseph Silk
[Abridged] Recently, the production of primordial black holes (PBHs) and secondary gravitational waves (GWs) due to enhanced scalar power on small scales have garnered considerable…
PBHs and secondary GWs from ultra slow roll and punctuated inflation
H. V. Ragavendra, Pankaj Saha, L. Sriramkumar +1
[Abridged] The primordial scalar power spectrum is well constrained on large scales, primarily by the observations of the anisotropies in the cosmic microwave background (CMB). Ove…
Suppression of scalar power on large scales and associated bispectra
H. V. Ragavendra, Debika Chowdhury, L. Sriramkumar
[Abridged] A sharp cut-off in the primordial scalar power spectrum on large scales has been known to improve the fit to the cosmic microwave background (CMB) data when compared to…
Unique contributions to the scalar bispectrum in `just enough inflation'
H. V. Ragavendra, Debika Chowdhury, L. Sriramkumar
A scalar field rolling down a potential with a large initial velocity results in inflation of a finite duration. Such a scenario suppresses the scalar power on large scales improvi…