Publications (24)
Shadow of higher dimensional collapsing dark star and blackhole
Sagnik Roy, Soham Chatterjee, Ratna Koley
The shadow of a black hole or a collapsing star is of great importance as we can extract important properties of the object and of the surrounding spacetime from the shadow profile…
Inflationary field excursion in broad classes of scalar field models
Argha Banerjee, Ratna Koley
In single field slow roll inflation models the height and slope of the potential are to satisfy certain conditions, to match with observations. This in turn translates into bounds…
Bulk phantom fields, increasing warp factors and fermion localisation
Ratna Koley, Sayan Kar
A bulk phantom scalar field (with negative kinetic energy) in a sine--Gordon type potential is used to generate an exact thick brane solution with an increasing warp factor. It is…
Magnetogenesis in Matter - Ekpyrotic Bouncing Cosmology
Ratna Koley, Sidhartha Samtani
In the recent past there have been many attempts to associate the generation of primordial magnetic seed fields with the inflationary era, but with limited success. We thus take a…
Scalar kinks and fermion localisation in warped spacetimes
Ratna Koley, Sayan Kar
Scalar kinks propagating along the bulk in warped spacetimes provide a thick brane realisation of the braneworld. We consider here, a class of such exact solutions of the full Eins…
Scalar and Spinor Quasi Normal Modes of a 2D Dilatonic Blackhole
Pabitra Gayen, Ratna Koley
External non-minimally coupled scalar and spinor field perturbations have been studied in a (1 + 1) dimensional dilatonic blackhole spacetime [1, 2]. Exact analytical expressions o…