857 citations · 4.9k across the 68 of their papers we have counts for
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A short note on the curvature perturbation at second order
Adam J. Christopherson, Ellie Nalson, Karim A. Malik
Working with perturbations about an FLRW spacetime, we compute the gauge-invariant curvature perturbation to second order solely in terms of scalar field fluctuations. Using the cu…
Conserved Quantities in Lemaitre-Tolman-Bondi Cosmology
Alexander Leithes, Karim A. Malik
We study linear perturbations to a Lema{\^ı}tre-Tolman-Bondi (LTB) background spacetime. Studying the transformation behaviour of the perturbations under gauge transformations, we…
Formation of subhorizon black holes from preheating
E. Torres-Lomas, Juan Carlos Hidalgo, Karim A. Malik +1
We study the production of primordial black holes (PBHs) during the preheating stage that follows a chaotic inflationary phase. The scalar fields present in the process are evolved…