186 citations · 450 across the 22 of their papers we have counts for
23 papers
Dark Matter as an Inflationary Relic in Warm Inflation
Swagat S. Mishra, Umang Kumar, Suratna Das +1
Warm inflation is usually expected to completely deplete the inflaton condensate by dissipating its energy into radiation. We show that this expectation fails in a simple and obser…
Eigenvalue formulation of Stochastic Inflation and application to large perturbation generating inflationary features
Swagat S. Mishra, Edmund J. Copeland, Anne M. Green
Stochastic inflation is a powerful technique for calculating the probability distribution function (PDF) of large inflationary perturbations, which may collapse to form Primordial…
Effective Phantom Dark Energy: What Cosmological Reconstruction Does and Does Not Imply
Swagat S. Mishra
In observational cosmology, the dark energy density and equation of state are effective quantities reconstructed at the background level under a set of assumptions. These include t…
Morphology of Inflationary Gravitational Wave Spectra imprinted by a Sequence of Post-Inflationary Epochs
Swagat S. Mishra, Athul K. Soman
The expansion history of the Universe prior to Big Bang Nucleosynthesis (BBN) remains largely unconstrained. The high-energy post-inflationary era may involve multiple distinct epo…
Witten-O'Raifeartaigh potential revisited in the context of Warm Inflation
Suratna Das, Umang Kumar, Swagat S. Mishra +1
Warm Inflation is a scenario in which the inflaton field dissipates its energy during inflation to maintain a subdominant constant radiation bath. Two of its remarkable features ar…
Braneworld Dark Energy in light of DESI DR2
Swagat S. Mishra, William L. Matthewson, Varun Sahni +2
Recent observational results from the DESI collaboration reveal tensions with the standard CDM model and favour a scenario in which dark energy (DE) decays over time. The DESI D…
Inflationary Gravitational Waves as a probe of the unknown post-inflationary primordial Universe
Athul K. Soman, Swagat S. Mishra, Mohammed Shafi +1
One of the key predictions of the standard inflationary paradigm is the quantum mechanical generation of the transverse and traceless tensor fluctuations due to the rapid accelerat…
Formation and decay of oscillons after inflation in the presence of an external coupling, Part-I: Lattice simulations
Mohammed Shafi, Edmund J. Copeland, Rafid Mahbub +2
We investigate the formation and decay of oscillons during the post-inflationary reheating epoch from inflaton oscillations around asymptotically flat potentials in the pres…
Cosmic Inflation: Background dynamics, Quantum fluctuations and Reheating
Swagat S. Mishra
These lecture notes provide a pedagogical introduction to some aspects of the inflationary cosmology, including the background scalar field dynamics, generation of primordial seed…
New models of Quintessential Inflation featuring plateau and hilltop potentials
Swagat S. Mishra, Varun Sahni
We introduce a new class of hilltop and plateau potentials which can successfully unify inflation and dark energy resulting in Quintessential Inflation (QI). Interestingly these ne…
Primordial black holes and stochastic inflation beyond slow roll: I -- noise matrix elements
Swagat S. Mishra, Edmund J. Copeland, Anne M. Green
Primordial Black Holes (PBHs) may form in the early Universe, from the gravitational collapse of large density perturbations, generated by large quantum fluctuations during inflati…
Oscillon formation from preheating in asymmetric inflationary potentials
Rafid Mahbub, Swagat S. Mishra
We investigate the possibility of oscillon formation during the preheating phase of asymmetric inflationary potentials. We analytically establish the existence of oscillon-like sol…
Numerical simulations of inflationary dynamics: slow roll and beyond
Siddharth S. Bhatt, Swagat S. Mishra, Soumen Basak +1
Numerical simulations of the inflationary dynamics are presented here for a single canonical scalar field minimally coupled to gravity. We spell out the basic equations governing t…
Tabletop potentials for inflation from gravity
Yuri Shtanov, Varun Sahni, Swagat S. Mishra
We show that a large class of modified gravity theories (MOG) with the Jordan-frame Lagrangian translate into scalar-field (scalaron) models with hilltop potentials in the E…
Canonical and Non-canonical Inflation in the light of the recent BICEP/Keck results
Swagat S. Mishra, Varun Sahni
We discuss implications of the latest BICEP/Keck data release for inflationary models, with particular emphasis on scalar fields with non-canonical Lagrangians of the type ${\cal L…
Curing inflationary degeneracies using reheating predictions and relic gravitational waves
Swagat S. Mishra, Varun Sahni, Alexei A. Starobinsky
It is well known that the inflationary scenario often displays different sets of degeneracies in its predictions for CMB observables. These degeneracies usually arise either becaus…
Generality of Starobinsky and Higgs inflation in the Jordan frame
Swagat S. Mishra, Daniel Müller, Aleksey V. Toporensky
We revisit the problem of generality of Starobinsky and Higgs inflation. The known results obtained in the Einstein frame are generalized for the case of an arbitrary initial energ…
Primordial Black Holes from a tiny bump/dip in the Inflaton potential
Swagat S. Mishra, Varun Sahni
Scalar perturbations during inflation can be substantially amplified by tiny features in the inflaton potential. A bump-like feature behaves like a local speed-breaker and lowers t…
Emulating CDM-like expansion on the Phantom brane
Satadru Bag, Swagat S. Mishra, Varun Sahni
In [Schmidt PRD 80 123003 (2009)], the author suggested that dynamical dark energy (DDE) propagating on the phantom brane could mimick CDM. Schmidt went on to derive a phenomeno…
Unifying Dark Matter and Dark Energy with non-Canonical Scalars
Swagat S. Mishra, Varun Sahni
Non-canonical scalar fields with the Lagrangian , possess the attractive property that the speed of sound, , can be exceedingly smal…
Initial conditions for Inflation in an FRW Universe
Swagat S. Mishra, Varun Sahni, Alexey V. Toporensky
We examine the class of initial conditions which give rise to inflation. Our analysis is carried out for several popular models including: Higgs inflation, Starobinsky inflation, c…
New tracker models of dark energy
Satadru Bag, Swagat S. Mishra, Varun Sahni
We describe a new class of dark energy (DE) models which behave like cosmological trackers at early times. These models are based on the -attractor set of potentials, originally…
Sourcing Dark Matter and Dark Energy from -attractors
Swagat S. Mishra, Varun Sahni, Yuri Shtanov
Recently, Kallosh and Linde have drawn attention to a new family of superconformal inflationary potentials, subsequently called -attractors. The -attractor family can interpo…