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; |
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Thesis |
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Publisher |
IOP Publishing Ltd |
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Language |
English |
Summary Language |
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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 ![sorted by ISSN field, descending order (down)](img/sort_desc.gif) |
1475-7516 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
|
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 |
Alencar, G.; Estrada, M.; Muniz, C.R.; Olmo, G.J. |
Title |
Dymnikova GUP-corrected black holes |
Type |
Journal Article |
Year |
2023 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
Volume |
11 |
Issue |
11 |
Pages |
100 - 23pp |
Keywords |
Exact solutions; black holes and black hole thermodynamics in GR and beyond; GR black holes; modified gravity; quantum black holes |
Abstract |
We consider the impact of Generalized Uncertainty Principle (GUP) effects on the Dymnikova regular black hole. The minimum length scale introduced by the GUP modifies the energy density associated with the gravitational source, referred to as the Dymnikova vacuum, based on its analogy with the gravitational counterpart of the Schwinger effect. We present an approximated analytical solution (together with exact numerical results for comparison) that encompasses a wide range of black hole sizes, whose properties crucially depend on the ratio between the de Sitter core radius and the GUP scale. The emergence of a wormhole inside the de Sitter core in the innermost region of the object is one of the most relevant features of this family of solutions. Our findings demonstrate that these solutions remain singularity free, confirming the robustness of the Dymnikova regular black hole under GUP corrections. Regarding energy conditions, we find that the violation of the strong, weak, and null energy conditions which is characteristic of the pure Dymnikova case does not occur at Planckian scales in the GUP corrected solution. This contrast suggests a departure from conventional expectations and highlights the influence of quantum corrections and the GUP in modifying the energy conditions near the Planck scale. |
Address |
[Alencar, G.; Olmo, Gonzalo J.] Univ Fed Ceara, Dept Fis, Caixa Postal 6030,Campus Pici, BR-60455760 Fortaleza, Ceara, Brazil, Email: geova@fisica.ufc.br; |
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Thesis |
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Publisher |
IOP Publishing Ltd |
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English |
Summary Language |
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Abbreviated Series Title |
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ISSN ![sorted by ISSN field, descending order (down)](img/sort_desc.gif) |
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:001121623400017 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
5868 |
Permanent link to this record |
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Author |
Chakraborty, S.; Gupta, A.; Vanvlasselaer, M. |
Title |
Anomaly induced cooling of neutron stars: a Standard Model contribution |
Type |
Journal Article |
Year |
2023 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
Volume |
10 |
Issue |
10 |
Pages |
030 - 23pp |
Keywords |
neutron stars; neutrino theory |
Abstract |
Young neutron stars cool via the emission of neutrinos from their core. A precise understanding of all the different processes producing neutrinos in the hot and degenerate matter is essential for assessing the cooling rate of such stars. The main Standard Model processes contributing to this effect are nu bremsstrahlung, mURCA among others. In this paper, we investigate another Standard Model process initiated by the Wess-Zumino-Witten term, leading to the emission of neutrino pairs via N gamma -> N nu nu over bar . We find that for proto-neutron stars, such processes with degenerate neutrons can be comparable and even dominate over the typical and well-known cooling mechanisms. |
Address |
[Chakraborty, Sabyasachi] Indian Inst Technol, Dept Phys, Kanpur 208016, India, Email: sabyac@iitk.ac.in; |
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Thesis |
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Publisher |
IOP Publishing Ltd |
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Editor |
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Language |
English |
Summary Language |
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Series Editor |
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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 ![sorted by ISSN field, descending order (down)](img/sort_desc.gif) |
1475-7516 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
|
Notes |
WOS:001116545800007 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
5872 |
Permanent link to this record |
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Author |
Forconi, M.; Ruchika; Melchiorri, A.; Mena, O.; Menci, N. |
Title |
Do the early galaxies observed by JWST disagree with Planck's CMB polarization measurements? |
Type |
Journal Article |
Year |
2023 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
Volume |
10 |
Issue |
10 |
Pages |
012 - 16pp |
Keywords |
cosmological parameters from CMBR; high redshift galaxies; CMBR polarisation; reionization |
Abstract |
The recent observations from the James Webb Space Telescope have led to a surprising discovery of a significant density of massive galaxies with masses of M >= 10(10.5)M(circle dot) at redshifts of approximately z similar to 10. This corresponds to a stellar mass density of roughly rho* similar to 10(6)M(circle dot) Mpc(-3). Despite making conservative assumptions regarding galaxy formation, this finding may not be compatible with the standard.CDM cosmology that is favored by observations of CMB Anisotropies from the Planck satellite. In this paper, we confirm the substantial discrepancy with Planck's results within the.CDM framework. Assuming a value of is an element of = 0.2 for the efficiency of converting baryons into stars, we indeed find that the.CDM model is excluded at more than 99.7% confidence level (C.L.). An even more significant exclusion is found for is an element of similar to 0.1, while a better agreement, but still in tension at more than 95%, is obtained for is an element of = 0.32. This tension, as already discussed in the literature, could arise either from systematics in the JWST measurements or from new physics. Here, as a last-ditch effort, we point out that disregarding the large angular scale polarization obtained by Planck, which allows for significantly larger values of the matter clustering parameter sigma(8), could lead to better agreement between Planck and JWST within the.CDM framework. Assuming.CDM and no systematics in the current JWST results, this implies either an unknown systematic error in current large angular scale CMB polarization measurements or an unidentified physical mechanism that could lower the expected amount of CMB polarization produced during the epoch of reionization. Interestingly, the model compatible with Planck temperature-only data and JWST observation also favors a higher Hubble constant H-0 = 69.0 +/- 1.1 km/s/Mpc at 68% C.L., in better agreement with observations based on SN-Ia luminosity distances. |
Address |
[Forconi, Matteo; Ruchika; Melchiorri, Alessandro] Univ Roma La Sapienza, Phys Dept, Ple Aldo Moro 2, I-00185 Rome, Italy, Email: matteo.forconi@roma1.infn.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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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 ![sorted by ISSN field, descending order (down)](img/sort_desc.gif) |
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:001142721200001 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
5903 |
Permanent link to this record |
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Author |
Maji, R.; Park, W.I. |
Title |
Supersymmetric U(1)B-L flat direction and NANOGrav 15 year data |
Type |
Journal Article |
Year |
2024 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
Volume |
01 |
Issue |
1 |
Pages |
015 - 19pp |
Keywords |
Cosmic strings; domain walls; monopoles; cosmological phase transitions; cosmology of theories beyond the SM; gravitational waves / sources |
Abstract |
We show that, when connected with monopoles, the flat D-flat direction breaking the local U(1)B-L symmetry as an extension of the minimal supersymmetric standard model can be responsible for the signal of a stochastic gravitational wave background recently reported by NANOGrav collaborations, while naturally satisfying constraints at high frequency band. Thanks to the flatness of the direction, a phase of thermal inflation arises naturally. The reheating temperature is quite low, and suppresses signals at frequencies higher than the characteristic frequency set by the reheating temperature. Notably, forthcoming spaced based experiments such as LISA can probe the cutoff frequency, providing an indirect clue of the scale of soft SUSY-breaking mass parameter. |
Address |
[Maji, Rinku] Jeonbuk Natl Univ, Dept Phys, Lab Symmetry & Struct Universe, Jeonju 54896, South Korea, Email: rinkumaji9792@gmail.com; |
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 ![sorted by ISSN field, descending order (down)](img/sort_desc.gif) |
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:001147733000001 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
5967 |
Permanent link to this record |
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Author |
Jeong, K.S.; Park, W.I. |
Title |
Cosmology with a supersymmetric local B – L model |
Type |
Journal Article |
Year |
2023 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
Volume |
11 |
Issue |
11 |
Pages |
016 - 34pp |
Keywords |
cosmological phase transitions; gravitational waves / sources; physics of the early universe; supersymmetry and cosmology |
Abstract |
We propose a minimal gauged U(1)(B-L) extension of the minimal supersymmetric Standard Model (MSSM) which resolves the cosmological moduli problem via thermal inflation, and realizes late-time Affleck-Dine leptogensis so as to generate the right amount of baryon asymmetry at the end of thermal inflation. The present relic density of dark matter can be explained by sneutrinos, MSSM neutralinos, axinos, or axions. Cosmic strings from U(1)(B-L) breaking are very thick, and so the expected stochastic gravitational wave background from cosmic string loops has a spectrum different from the one in the conventional Abelian-Higgs model, as would be distinguishable at least at LISA and DECIGO. The characteristic spectrum is due to a flat potential, and may be regarded as a hint of supersymmetry. Combined with the resolution of moduli problem, the expected signal of gravitational waves constrains the U(1)(B-L) breaking scale to be O(10(12-13)) GeV. Interestingly, our model provides a natural possibility for explaining the observed ultra-high-energy cosmic rays thanks to the fact that the core width of strings in our scenario is very large, allowing a large enhancement of particle emissions from the cusps of string loops. Condensation of LHu flat-direction inside of string cores arises inevitably and can also be the main source of the ultra-high-energy cosmic rays accompanied by ultra-high-energy lightest supersymmetric particles. |
Address |
[Jeong, Kwang Sik] Pusan Natl Univ, Dept Phys, Busan 46241, South Korea, Email: ksjeong@pusan.ac.kr; |
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Publisher |
IOP Publishing Ltd |
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Editor |
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English |
Summary Language |
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Original Title |
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Series Editor |
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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 ![sorted by ISSN field, descending order (down)](img/sort_desc.gif) |
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:001149204000015 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
5992 |
Permanent link to this record |
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Author |
Balaudo, A.; Calore, F.; De Romeri, V.; Donato, F. |
Title |
NAJADS: a self-contained framework for the direct determination of astrophysical J-factors |
Type |
Journal Article |
Year |
2024 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
Volume |
02 |
Issue |
2 |
Pages |
001 - 33pp |
Keywords |
dark matter simulations; dark matter theory; dark matter detectors |
Abstract |
Cosmological simulations play a pivotal role in understanding the properties of the dark matter (DM) distribution in both galactic and galaxy -cluster environments. The characterization of DM structures is crucial for informing indirect DM searches, aiming at the detection of the annihilation (or decay) products of DM particles. A fundamental quantity in these analyses is the astrophysical J -factor. In the DM phenomenology community, J -factors are typically computed through the semi -analytical modelling of the DM mass distribution, which is affected by large uncertainties. With the scope of addressing and possibly reducing these uncertainties, we present NAJADS, a self-contained framework to derive the DM J -factor directly from the raw simulations data. We show how this framework can be used to compute all -sky maps of the J -factor, automatically accounting for the complex 3D structure of the simulated halos and for the boosting of the signal due to the density fluctuations along the line of sight. After validating our code, we present a proof -of -concept application of NAJADS to a realistic halo from the IllustrisTNG suite, and exploit it to make a thorough comparison between our numerical approach and traditional semi -analytical methods. JCAP02(2024)001 |
Address |
[Balaudo, Anna] Leiden Univ, Leiden Observ, POB 9513, NL-2300 RA Leiden, Netherlands, Email: balaudo@strw.leidenuniv.nl; |
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Publisher |
IOP Publishing Ltd |
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English |
Summary Language |
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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 ![sorted by ISSN field, descending order (down)](img/sort_desc.gif) |
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:001182021200006 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
6018 |
Permanent link to this record |
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Author |
Domcke, V.; Ema, Y.; Sandner, S. |
Title |
Perturbatively including inhomogeneities in axion inflation |
Type |
Journal Article |
Year |
2024 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
Volume |
03 |
Issue |
3 |
Pages |
019 - 24pp |
Keywords |
axions; inflation; particle physics- cosmology connection |
Abstract |
Axion inflation, i.e. an axion-like inflaton coupled to an Abelian gauge field through a Chern-Simons interaction, comes with a rich and testable phenomenology. This is particularly true in the strong backreaction regime, where the gauge field production heavily impacts the axion dynamics. Lattice simulations have recently demonstrated the importance of accounting for inhomogeneities of the axion field in this regime. We propose a perturbative scheme to account for these inhomogeneities while maintaining high computational efficiency. Our goal is to accurately capture deviations from the homogeneous axion field approximation within the perturbative regime as well as self -consistently determine the onset of the nonperturbative regime. |
Address |
[Domcke, Valerie] CERN, Theoret Phys Dept, Geneva 23, Switzerland, Email: valerie.domcke@cern.ch; |
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Thesis |
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Publisher |
IOP Publishing Ltd |
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English |
Summary Language |
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Edition |
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ISSN ![sorted by ISSN field, descending order (down)](img/sort_desc.gif) |
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:001185016600002 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
6020 |
Permanent link to this record |
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Author |
Santos, A.C.L.; Muniz, C.R.; Maluf, R.V. |
Title |
Yang-Mills Casimir wormholes in D=2+1 |
Type |
Journal Article |
Year |
2023 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
Volume |
09 |
Issue |
9 |
Pages |
022 - 24pp |
Keywords |
Wormholes; Exact solutions; black holes and black hole thermodynamics in GR and beyond; gravity |
Abstract |
This work presents new three-dimensional traversable wormhole solutions sourced by the Casimir density and pressures related to the quantum vacuum fluctuations in Yang-Mills (Y-M) theory. We begin by analyzing the noninteracting Y-M Casimir wormholes, initially considering an arbitrary state parameter omega and determine a simple constant wormhole shape function. Next, we introduce a new methodology for deforming the state parameter to find well-behaved redshift functions. The wormhole can be interpreted as a legitimate Casimir wormhole with an expected average state parameter of omega = 2. Then, we investigate the wormhole curvature properties, energy conditions, and stability. Furthermore, we discover a novel family of traversable wormhole solutions sourced by the quantum vacuum fluctuations of interacting Yang-Mills fields with a more complex shape function. Deforming the effective state parameter similarly, we obtain well-behaved redshift functions and traversable wormhole solutions. Finally, we examine the energy conditions and stability of solutions in the interacting scenario and compare to the noninteracting case. |
Address |
[Santos, Alana C. L.; Maluf, Roberto V.] Univ Fed Ceara UFC, Departamento Fis, Campus Pici,6030, BR-60455760 Fortaleza, Ceara, Brazil, Email: alanasantos@fisica.ufc.br; |
Corporate Author |
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Publisher |
IOP Publishing Ltd |
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Editor |
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English |
Summary Language |
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Series Editor |
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Abbreviated Series Title |
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Series Volume |
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Edition |
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ISSN ![sorted by ISSN field, descending order (down)](img/sort_desc.gif) |
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:001196198800004 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
6031 |
Permanent link to this record |
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Author |
Amerio, A.; Calore, F.; Serpico, P.D.; Zaldivar, B. |
Title |
Deepening gamma-ray point-source catalogues with sub-threshold information |
Type |
Journal Article |
Year |
2024 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
Volume |
03 |
Issue |
3 |
Pages |
055 - 18pp |
Keywords |
gamma ray theory; Frequentist statistics |
Abstract |
We propose a novel statistical method to extend Fermi-LAT catalogues of highlatitude -y-ray sources below their nominal threshold. To do so, we rely on the determination of the differential source -count distribution of sub -threshold sources which only provides the statistical flux distribution of faint sources. By simulating ensembles of synthetic skies, we assess quantitatively the likelihood for pixels in the sky with relatively low -test statistics to be due to sources, therefore complementing the source -count distribution with spatial information. Besides being useful to orient efforts towards multi -messenger and multi -wavelength identification of new -y-ray sources, we expect the results to be especially advantageous for statistical applications such as cross -correlation analyses. |
Address |
[Amerio, Aurelio; Zaldivar, Bryan] Univ Valencia, Inst Fis Corpuscular IFIC, Calle Catedrat Jose Beltran 2, Paterna 46980, Spain, Email: aurelio.amerio@ific.uv.es; |
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 ![sorted by ISSN field, descending order (down)](img/sort_desc.gif) |
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:001194945600003 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
6032 |
Permanent link to this record |