145 citations · 2.1k across the 96 of their papers we have counts for
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New Hamiltonians for loop quantum cosmology with arbitrary spin representations
Jibril Ben Achour, Suddhasattwa Brahma, Marc Geiller
In loop quantum cosmology, one has to make a choice of SU(2) irreducible representation in which to compute holonomies and regularize the curvature of the connection. The systemati…
Non Bunch Davies group coherent states, and their quantum signatures in CMB observables
Pietro Dona, Antonino Marciano
We approach the problem of finding generalized states for matter fields in a de Sitter universe, moving from a group theoretical point of view. This has profound consequences for c…
Signature change in 2-dimensional black-hole models of loop quantum gravity
Martin Bojowald, Suddhasattwa Brahma
Signature change has been identified as a generic consequence of holonomy modifications in spherically symmetric models of loop quantum gravity with real connections, which include…
Signature change in loop quantum gravity: General midisuperspace models and dilaton gravity
Martin Bojowald, Suddhasattwa Brahma
Models of loop quantum gravity based on real connections have a deformed notion of general covariance, which leads to the phenomenon of signature change. This result is confirmed h…
Monopole star products are non-alternative
Martin Bojowald, Suddhasattwa Brahma, Umut Buyukcam +1
Non-associative algebras appear in some quantum-mechanical systems, for instance if a charged particle in a distribution of magnetic monopoles is considered. Using methods of defor…
Hypersurface-deformation algebroids and effective space-time models
Martin Bojowald, Suddhasattwa Brahma, Umut Buyukcam +1
In canonical gravity, covariance is implemented by brackets of hypersurface-deformation generators forming a Lie algebroid. Lie algebroid morphisms therefore allow one to relate di…
Linking loop quantum gravity quantization ambiguities with phenomenology
Suddhasattwa Brahma, Michele Ronco, Giovanni Amelino-Camelia +1
Fundamental quantum gravity theories are known to be notoriously difficult to extract viable testable predictions out of. In this paper, we aim to incorporate putative quantum corr…
A new look at scalar perturbations in loop quantum cosmology: (un)deformed algebra approach using self dual variables
Jibril Ben Achour, Suddhasattwa Brahma, Julien Grain +1
Scalar cosmological perturbations in loop quantum cosmology (LQC) is revisited in a covariant manner, using self dual Ashtekar variables. For real-valued Ashtekar-Barbero variables…
Spherically symmetric sector of self dual Ashtekar gravity coupled to matter: Anomaly-free algebra of constraints with holonomy corrections
Jibril Ben Achour, Suddhasattwa Brahma, Antonino Marciano
Using self dual Ashtekar variables, we investigate (at the effective level) the spherically symmetry reduced model of loop quantum gravity, both in vacuum and when coupled to a sca…