145 citations · 2.1k across the 96 of their papers we have counts for
16 papers · 1 filter
Testing loop quantum gravity from observational consequences of non-singular rotating black holes
Suddhasattwa Brahma, Che-Yu Chen, Dong-han Yeom
The lack of rotating black hole models, which are typically found in nature, in loop quantum gravity (LQG) substantially hinders the progress of testing LQG from observations. Star…
The ground state of non-associative hydrogen and upper bounds on the magnetic charge of elementary particles
Martin Bojowald, Suddhasattwa Brahma, Umut Buyukcam +1
Formulations of magnetic monopoles in a Hilbert-space formulation of quantum mechanics require Dirac's quantization condition of magnetic charge, which implies a large value that c…
Multi-field inflation from single-field models
Martin Bojowald, Suddhasattwa Brahma, Sean Crowe +2
Quantization implies independent degrees of freedom that do not appear in the classical theory, given by fluctuations, correlations, and higher moments of a state. A systematic der…
Quantum Higgs Inflation
Martin Bojowald, Suddhasattwa Brahma, Sean Crowe +2
The Higgs field is an attractive candidate for the inflaton because it is an observationally confirmed fundamental scalar field. Importantly, it can be modeled by the most general…
Loop quantum gravity, signature change, and the no-boundary proposal
Martin Bojowald, Suddhasattwa Brahma
Covariant models of loop quantum gravity generically imply dynamical signature change at high density. This article presents detailed derivations that show the fruitful interplay o…
Crisis on Infinite Earths: Short-lived de Sitter Vacua in the String Theory Landscape
Heliudson Bernardo, Suddhasattwa Brahma, Keshav Dasgupta +1
We construct purely non-perturbative anti-de Sitter vacua in string theory which, on uplifting to a de Sitter (dS) one, have a decay time many orders of magnitude smaller than thos…
Entanglement entropy of cosmological perturbations for S-brane Ekpyrosis
Suddhasattwa Brahma, Robert Brandenberger, Ziwei Wang
We calculate the entanglement entropy of scalar perturbations due to gravitational non-linearities present in any model of canonically-coupled, single-field ekpyrosis. Specifically…
de Sitter Space as a Glauber-Sudarshan State
Suddhasattwa Brahma, Keshav Dasgupta, Radu Tatar
Glauber-Sudarshan states, sometimes simply referred to as Glauber states, or alternatively as coherent and squeezed-coherent states, are interesting states in the configuration spa…
Consistency of Cubic Galileon Cosmology: Model-Independent Bounds from Background Expansion and Perturbative Analyses
Suddhasattwa Brahma, Md. Wali Hossain
We revisit the cosmological dynamics of the cubic Galileon model in light of the recently proposed model-independent analyses of the Pantheon supernova data. At the background leve…
Four-dimensional de Sitter space is a Glauber-Sudarshan state in string theory
Suddhasattwa Brahma, Keshav Dasgupta, Radu Tatar
We show that four-dimensional de Sitter space is a Glauber-Sudarshan state, i.e. a coherent state, over a supersymmetric solitonic background in full string theory. We argue that s…
Entanglement Entropy of Cosmological Perturbations
Suddhasattwa Brahma, Omar Alaryani, Robert Brandenberger
We show that the entropy of cosmological perturbations originating as quantum vacuum fluctuations in the very early universe, including the contribution of the leading nonlinear in…
A consistent model of non-singular Schwarzschild black hole in loop quantum gravity and its quasinormal modes
Mariam Bouhmadi-López, Suddhasattwa Brahma, Che-Yu Chen +2
We investigate the interior structure, perturbations, and the associated quasinormal modes of a quantum black hole model recently proposed by Bodendorfer, Mele, and Münch (BMM). Wi…
Towards consistent black-to-white hole bounces from matter collapse
Jibril Ben Achour, Suddhasattwa Brahma, Shinji Mukohyama +1
This article presents a new model-independent constraint for bouncing black hole geometries. Using the thin shell formalism, this constraint sets a bound on the minimal allowed rad…
Role of trans-Planckian modes in cosmology
Arjun Berera, Suddhasattwa Brahma, Jaime R. Calderón
Motivated by the old trans-Planckian (TP) problem of inflationary cosmology, it has been conjectured that any consistent effective field theory should keep TP modes `hidden' behind…
Swampland, Trans-Planckian Censorship and Fine-Tuning Problem for Inflation: Tunnelling Wavefunction to the Rescue
Suddhasattwa Brahma, Robert Brandenberger, Dong-han Yeom
The trans-Planckian censorship conjecture implies that single-field models of inflation require an extreme fine-tuning of the initial conditions due to the very low-scale of inflat…
Bouncing compact objects I: Quantum extension of the Oppenheimer-Snyder collapse
Jibril Ben Achour, Suddhasattwa Brahma, Jean-Philippe Uzan
This article proposes a generalization of the Oppenheimer-Snyder model which describes a bouncing compact object. The corrections responsible for the bounce are parameterized in a…