| Records |
Author  |
Boudet, S.; Bombacigno, F.; Moretti, F.; Olmo, G.J. |
| Title |
Torsional birefringence in metric-affine Chern-Simons gravity: gravitational waves in late-time cosmology |
Type |
Journal Article |
| Year |
2023 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
| Volume |
01 |
Issue |
1 |
Pages |
026 - 28pp |
| Keywords |
Gravitational waves in GR and beyond: theory; modified gravity; Cosmological perturbation theory in GR and beyond; Exact solutions; black holes and black hole thermodynamics in GR and beyond |
| Abstract |
In the context of the metric-affine Chern-Simons gravity endowed with projective invariance, we derive analytical solutions for torsion and nonmetricity in the homogeneous and isotropic cosmological case, described by a flat Friedmann-Robertson-Walker metric. We discuss in some details the general properties of the cosmological solutions in the presence of a perfect fluid, such as the dynamical stability and the emergence of big bounce points, and we examine the structure of some specific solutions reproducing de Sitter and power law behaviours for the scale factor. Then, we focus on first-order perturbations in the de Sitter scenario, and we study the propagation of gravitational waves in the adiabatic limit, looking at tensor and scalar polarizations. In particular, we find that metric tensor modes couple to torsion tensor components, leading to the appearance, as in the metric version of Chern-Simons gravity, of birefringence, characterized by different dispersion relations for the left and right circularized polarization states. As a result, the purely tensor part of torsion propagates like a wave, while nonmetricity decouples and behaves like a harmonic oscillator. Finally, we discuss scalar modes, outlining as they decay exponentially in time and do not propagate. |
| Address |
[Boudet, S.] Univ Trento, Dipartimento Fis, Via Sommar 14, I-38123 Povo, TN, Italy, Email: simon.boudet@unitn.it; |
| Corporate Author |
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Thesis |
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| Publisher |
IOP Publishing Ltd |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
1475-7516 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:001090397800016 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5791 |
| Permanent link to this record |
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| Author |
Bernal, N.; Munoz-Albornoz, V.; Palomares-Ruiz, S.; Villanueva-Domingo, P. |
| Title |
Current and future neutrino limits on the abundance of primordial black holes |
Type |
Journal Article |
| Year |
2022 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
| Volume |
10 |
Issue |
10 |
Pages |
068 - 38pp |
| Keywords |
neutrino detectors; primordial black holes |
| Abstract |
Primordial black holes (PBHs) formed in the early Universe are sources of neutrinos emitted via Hawking radiation. Such astrophysical neutrinos could be detected at Earth and constraints on the abundance of comet-mass PBHs could be derived from the null observation of this neutrino flux. Here, we consider non-rotating PBHs and improve constraints using Super-Kamiokande neutrino data, as well as we perform forecasts for next-generation neutrino (Hyper-Kamiokande, JUNO, DUNE) and dark matter (DARWIN, ARGO) detectors, which we compare. For PBHs less massive than " few x 1014 g, PBHs would have already evaporated by now, whereas more massive PBHs would still be present and would constitute a fraction of the dark matter of the Universe. We consider monochromatic and extended (log-normal) mass distributions, and a PBH mass range spanning from 1012 g to ti 1016 g. Finally, we also compare our results with previous ones in the literature. |
| Address |
[Bernal, Nicolas] New York Univ Abu Dhabi, POB 129188, Abu Dhabi, U Arab Emirates, Email: nicolas.bernal@uan.edu.co; |
| Corporate Author |
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Thesis |
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| Publisher |
IOP Publishing Ltd |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
1475-7516 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:000882783900003 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5412 |
| Permanent link to this record |
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| Author |
Beltran Jimenez, J.; Heisenberg, L.; Olmo, G.J.; Rubiera-Garcia, D. |
| Title |
Born-Infeld inspired modifications of gravity |
Type |
Journal Article |
| Year |
2018 |
Publication |
Physics Reports |
Abbreviated Journal |
Phys. Rep. |
| Volume |
727 |
Issue |
|
Pages |
1-129 |
| Keywords |
Born-Infeld gravity; Astrophysics; Black holes; Cosmology; Early universe; Compact objects; Singularities |
| Abstract |
General Relativity has shown an outstanding observational success in the scales where it has been directly tested. However, modifications have been intensively explored in the regimes where it seems either incomplete or signals its own limit of validity. In particular, the breakdown of unitarity near the Planck scale strongly suggests that General Relativity needs to be modified at high energies and quantum gravity effects are expected to be important. This is related to the existence of spacetime singularities when the solutions of General Relativity are extrapolated to regimes where curvatures are large. In this sense, Born-Infeld inspired modifications of gravity have shown an extraordinary ability to regularise the gravitational dynamics, leading to non-singular cosmologies and regular black hole spacetimes in a very robust manner and without resorting to quantum gravity effects. This has boosted the interest in these theories in applications to stellar structure, compact objects, inflationary scenarios, cosmological singularities, and black hole and wormhole physics, among others. We review the motivations, various formulations, and main results achieved within these theories, including their observational viability, and provide an overview of current open problems and future research opportunities. |
| Address |
[Beltran Jimenez, Jose] Univ Autonoma Madrid, CSIC, Inst Fis Teor, E-28049 Madrid, Spain, Email: jose.beltran@uam.es; |
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Thesis |
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| Publisher |
Elsevier Science Bv |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0370-1573 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:000425482900001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
3497 |
| Permanent link to this record |
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| Author |
Balbinot, R.; Fabbri, A. |
| Title |
The Hawking Effect in the Particles-Partners Correlations |
Type |
Journal Article |
| Year |
2023 |
Publication |
Physics |
Abbreviated Journal |
Physics |
| Volume |
5 |
Issue |
4 |
Pages |
968-982 |
| Keywords |
quantum fields in curved space; black holes; Hawking radiation; correlations across the horizon |
| Abstract |
We analyze the correlations functions across the horizon in Hawking black hole radiation to reveal the correlations between Hawking particles and their partners. The effects of the underlying space-time on this are shown in various examples ranging from acoustic black holes to regular black holes. |
| Address |
[Balbinot, Roberto] Univ Bologna, Dipartimento Fis, Via Irnerio 46, I-40126 Bologna, Italy, Email: roberto.balbinot@unibo.it; |
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Thesis |
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| Publisher |
Mdpi |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:001130983900001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5858 |
| Permanent link to this record |
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| Author |
Balbinot, R.; Fabbri, A. |
| Title |
The Unruh Vacuum and the “In-Vacuum” in Reissner-Nordström Spacetime |
Type |
Journal Article |
| Year |
2024 |
Publication |
Universe |
Abbreviated Journal |
Universe |
| Volume |
10 |
Issue |
1 |
Pages |
18 - 14pp |
| Keywords |
Hawking radiation; Unruh vacuum; Reissner-Nordstrom black holes |
| Abstract |
The Unruh vacuum is widely used as a quantum state to describe black hole evaporation since, near the horizon, it reproduces the physical state of a quantum field, the so-called “in-vacuum”, in the case where a black hole is formed by gravitational collapse. We examine the relation between these two quantum states in the background spacetime of a Reissner-Nordstrom black hole (both extremal and not), highlighting the similarities and striking differences. |
| Address |
[Balbinot, Roberto] Univ Bologna, Dipartimento Fis, Via Irnerio 46, I-40126 Bologna, Italy, Email: roberto.balbinot@unibo.it; |
| Corporate Author |
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Thesis |
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| Publisher |
Mdpi |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:001151025300001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5914 |
| Permanent link to this record |
