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@article{faucris.308216280,
abstract = {We investigate the cosmological applications of new gravitational scalar-tensor theories, and we analyze them in the light of H0 tension. In these theories, the Lagrangian contains the Ricci scalar and its first and second derivatives in a specific combination that makes them free of ghosts, thus corresponding to healthy biscalar extensions of general relativity. We examine two specific models, and for particular choices of the model parameters, we find that the effect of the additional terms is negligible at high redshifts, obtaining a coincidence with ΛCDM cosmology; however, as time passes, the deviation increases, and thus, at low redshifts the Hubble parameter acquires increased values (H0≈74 km/s/Mpc) in a controlled way. The mechanism behind this behavior is the fact that the effective dark-energy equation-of-state parameter exhibits phantom behavior, which implies faster expansion, which is one of the sufficient conditions that are capable of alleviating the H0 tension. Lastly, we confront the models with cosmic chronometer (CC) data, showing full agreement within 1σ confidence level. },
author = {Banerjee, Shreya and Petronikolou, Maria and Saridakis, Emmanuel N.},
doi = {10.1103/PhysRevD.108.024012},
faupublication = {yes},
journal = {Physical Review D},
note = {CRIS-Team Scopus Importer:2023-07-28},
peerreviewed = {Yes},
title = {{Alleviating} the {H0} tension with new gravitational scalar tensor theories},
volume = {108},
year = {2023}
}
@article{faucris.286928840,
abstract = {The phenomenology of primordial black hole (PBH) physics and the associated PBH abundance constraints can be used to probe the physics of the early universe. In this work, we investigate the PBH formation during the standard radiation-dominated era by studying the effect of an early F(R) modified gravity phase with a bouncing behavior which is introduced to avoid the initial spacetime singularity problem. In particular, we calculate the energy density power spectrum at horizon crossing time, and then we extract the PBH abundance in the context of peak theory as a function of the parameter α of our F(R) gravity bouncing model at hand. Interestingly, we find that to avoid gravitational-wave overproduction from an early PBH dominated era before big bang nucleosynthesis, α should lie within the range α≤10-19MPl2. This constraint can be translated to a constraint on the energy scale at the onset of the hot big bang phase, HRD∼α/2, which can be recast as HRD<10-10MPl. },
author = {Banerjee, Shreya and Papanikolaou, Theodoros and Saridakis, Emmanuel N.},
doi = {10.1103/PhysRevD.106.124012},
faupublication = {yes},
journal = {Physical Review D},
note = {CRIS-Team Scopus Importer:2022-12-23},
peerreviewed = {Yes},
title = {{Constraining} {F} ({R}) bouncing cosmologies through primordial black holes},
volume = {106},
year = {2022}
}
@article{faucris.266126318,
abstract = {Different forms of long gamma-ray burst (GRB) luminosity functions are considered on the basis of an explicit physical model. The inferred flux distributions are compared with the observed ones from two samples of GRBs, Swift and Fermi GBM. The best-fit parameters of the luminosity functions are found, and the physical interpretations are discussed. The results are consistent with the observation of a comparable number of flat-phase afterglows and monotonically decreasing ones.},
author = {Banerjee, Shreya and Eichler, David and Guetta, Dafne},
doi = {10.3847/1538-4357/ac1a6f},
faupublication = {yes},
journal = {Astrophysical Journal},
note = {CRIS-Team WoS Importer:2021-11-12},
peerreviewed = {Yes},
title = {{Differential} {Source} {Count} for {Gamma}-{Ray} {Bursts}},
volume = {921},
year = {2021}
}
@article{faucris.295410204,
abstract = {The Lambda-Cold Dark Matter model explains cosmological observations most accurately till date. However, it is still plagued with various shortcomings at galactic scales. Models of dark matter such as superfluid dark matter, Bose-Einstein Condensate(BEC) dark matter and fuzzy dark matter have been proposed to overcome some of these drawbacks. In this work, we probe these models using the current constraint on the gravitational wave (GW) propagation speed coming from the binary neutron star GW170817 detection by LIGO-Virgo detector network and use it to study the allowed parameter space for these three models for Advanced LIGO+Virgo, LISA, IPTA and SKA detection frequencies. The speed of GW has been shown to depend upon the refractive index of the medium, which in turn, depends on the dark matter model parameters through the density profile of the galactic halo. We constrain the parameter space for these models using the bounds coming from GW speed measurement and the Milky Way radius bound. Our findings suggest that with Advanced LIGO-Virgo detector sensitivity, the three models considered here remain unconstrained. A meaningful constraint can only be obtained for detection frequencies ≤ 10^{-9} Hz, which falls in the detection range of radio telescopes such as IPTA and SKA. Considering this best possible case, we find that out of the three condensate models, the fuzzy dark matter model is the most feasible scenario to be falsified/validated in near future.},
author = {Banerjee, Shreya and Bera, Sayantani and Mota, David F.},
doi = {10.1088/1475-7516/2023/03/041},
faupublication = {yes},
journal = {Journal of Cosmology and Astroparticle Physics},
keywords = {dark matter theory; gravitational waves / theory},
note = {CRIS-Team Scopus Importer:2023-04-07},
peerreviewed = {Yes},
title = {{Prospects} of probing dark matter condensates with gravitational waves},
volume = {2023},
year = {2023}
}
@article{faucris.311726833,
abstract = {Quantum cosmology aims to develop a quantum theory of the universe, attempting to answer open questions of physical cosmology, mainly related to the early epochs of the universe. Such a theory aims to unite relativity theory and quantum theory. Here, the whole universe is treated as a quantum mechanical system and is described by a wave function rather than by a classical spacetime. In this review, I shall describe the mathematical structure and primary formulations that form the backbone of quantum cosmology. We know that over a period of time, several approaches were developed to form a quantum theory of gravity. However, in order to decide which approach is the best, we need testable predictions, effects that can be observed in cosmic microwave background radiation (CMBR). I shall discuss the methodologies for generating quantum gravitational corrections to inflationary background leading to testable predictions. Another aspect of finding quantum imprints on CMBR results through the application of resolution of the ‘quantum measurement problem’ to early universe physics. In this article, I shall also discuss two such promising models explaining the classicalization of inflationary perturbation and are capable of leaving distinct observational imprints on the observables.},
author = {Banerjee, Shreya},
doi = {10.3390/universe9090405},
faupublication = {yes},
journal = {Universe},
keywords = {cosmic microwave background; inflation; quantum cosmology; Wheeler–DeWitt},
note = {CRIS-Team Scopus Importer:2023-10-06},
peerreviewed = {Yes},
title = {{Quantum} {Imprints} on {CMBR}},
volume = {9},
year = {2023}
}
@inproceedings{faucris.315102804,
abstract = {We investigate the cosmological applications of new gravitational scalar-tensor theories and we analyze them in the light of H0 tension. In these theories the Lagrangian contains the Ricci scalar and its first and second derivatives in a specific combination that makes them free of ghosts, thus corresponding to healthy bi-scalar extensions of general relativity. We examine two specific models, and for particular choices of the model parameters we find that the effect of the additional terms is negligible at high redshifts, obtaining a coincidence with ΛCDM cosmology, however as time passes the deviation increases and thus at low redshifts the Hubble parameter acquires increased values (H0 ≈ 74km/s/Mpc) in a controlled way. The mechanism behind this behavior is the fact that the effective dark-energy equation-of-state parameter exhibits phantom behavior, which implies faster expansion, which is one of the theoretical requirements that are capable of alleviating the H0 tension. Lastly, we confront the models with Cosmic Chronometer (CC) data showing full agreement within 1σ confidence level.},
author = {Banerjee, Shreya and Petronikolou, Maria and Saridakis, Emmanuel N.},
booktitle = {Proceedings of Science},
date = {2022-08-28/2022-10-01},
faupublication = {yes},
note = {CRIS-Team Scopus Importer:2023-12-15},
peerreviewed = {unknown},
publisher = {Sissa Medialab Srl},
title = {{Resolving} {Hubble} {Tension} with {New} {Gravitational} {Scalar} {Tensor} {Theories}},
venue = {Corfu, GRC},
volume = {436},
year = {2023}
}