Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
4.9
2.7
Journals
Symmetry
Special Issues
Probing the Universe with Gravitational Waves
share announcement

Probing the Universe with Gravitational Waves

A special issue of Symmetry (ISSN 2073-8994). This special issue belongs to the section "Physics".

Deadline for manuscript submissions: closed (30 November 2021) | Viewed by 15059

Special Issue Editors

Prof. José A. de Freitas Pacheco

E-Mail Website
Guest Editor
Observatoire de la Côte d’Azur, Laboratoire Lagrange, Parc Valrose, 06108 Nice, France
Interests: cosmology; general relativity; physics of compact objects; gravitational waves
Dr. Pasquale Bosso

E-Mail Website
Guest Editor
Department of Physics, University of Lethbridge, 4401 University Dr W, Lethbridge, AB T1K 3M4, Canada
Interests: theoretical physics; gravitation; quantum gravity; quantum mechanics

Special Issue Information

Dear Colleagues,

The detection of the first gravitational wave signal by the laser interferometer LIGO in September 2015 confirmed one of the predictions by Albert Einstein made almost a century ago. This detection represents a breakthrough on the experimental basis of General Relativity and the studies of compact objects like black holes and neutron stars. Moreover, gravitational waves open a new exploratory window of the early universe, since, beyond redshift ~ 1100, the universe is completely opaque to electromagnetic radiation. Hence, gravitational waves represent a unique way to probe the physical processes that may have occurred in the early universe.

Presently, the universe is dominated by matter and not by anti-matter. This asymmetry could be the consequence of various mechanisms and, in particular, the symmetry breaking between weak and electromagnetic interactions that may have occurred at temperatures around 100-200 GeV. During the phase transition between the symmetric and anti-symmetric states, copious gravitational waves are generated, which contribute to the expected cosmological gravitational wave background. Thus, the detection of such a signal would be an important source of information that will be able to confirm or disconfirm these theoretical expectations. Besides this mechanism, gravitational waves in the primordial universe could have been generated by field fluctuations during inflation or during the quark–hadron phase transition. Moreover, in a cosmological scenario in which a network of cosmic strings is present, gravitational waves can be also generated, contributing to the general cosmological background.

In this Special Issue, contributions covering all the above-mentioned physical aspects are expected, in particular:

  1. Gravitational waves generated in the primordial universe, with emphasis on the inflation, the electroweak transition, and the QCD transition
  2. Gravitational waves from cosmic strings
  3. Compact objects as gravitational wave sources
  4. The astrophysical gravitational wave background
  5. Detection of the gravitational wave background—ground-based and space-based antennas

Prof. José A. de Freitas Pacheco
Dr. Pasquale Bosso
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Symmetry is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • gravitational waves
  • early universe
  • sources of gravitational waves
  • detection of the gravitational wave background

Published Papers (5 papers)

Download All Papers
Order results
Result details
Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:

Research

10 pages, 1347 KiB  
Communication
An Eccentric Binary Blackhole in Post-Newtonian Theory
by Sourav Roy Chowdhury and Maxim Khlopov
Symmetry 2022, 14(3), 510; https://0-doi-org.brum.beds.ac.uk/10.3390/sym14030510 - 02 Mar 2022
Cited by 3 | Viewed by 1646
Abstract
Gravitational waves radiated during binary black hole coalescence are a perfect probe for studying the characteristics of strong gravity. Advanced techniques for creating numerical relativity substitute models for eccentric binary black hole systems are presumed to be crucial in existing and anticipated gravitational [...] Read more.
Gravitational waves radiated during binary black hole coalescence are a perfect probe for studying the characteristics of strong gravity. Advanced techniques for creating numerical relativity substitute models for eccentric binary black hole systems are presumed to be crucial in existing and anticipated gravitational wave detectors. The imprint on the observation data of the gravitational wave emitted by the binary coalescence enhances two-body system studies. The aim of this study is to present an overview of the change in characteristic behaviors of hierarchical massive astrophysical objects merger, which are the databank of the early universe. We present results from numerical relativity simulations of an equal-mass and unequal mass nonspinning inspiral binary-black-hole system in the Post-Newtonian framework. We also consider the time evolution of eccentricity for an initial eccentric system. The eccentric Post-Newtonian equations are expanded in the form of the frequency related variable x=(Mω)2/3. The model is restricted to the (2, 2) spin-weighted spherical harmonic modes. We conclude that for higher eccentricity as well as mass ratio, there is higher oscillation in orbital radius and in eccentricity. Full article
(This article belongs to the Special Issue Probing the Universe with Gravitational Waves)
►▼ Show Figures

Figure 1

25 pages, 2108 KiB  
Article
The Quest for the Astrophysical Gravitational-Wave Background with Terrestrial Detectors
by Tania Regimbau
Symmetry 2022, 14(2), 270; https://0-doi-org.brum.beds.ac.uk/10.3390/sym14020270 - 29 Jan 2022
Cited by 16 | Viewed by 5969
Abstract
We present the gravitational-wave background and its properties focusing on the background from compact binary coalescences in terrestrial detectors. We also introduce the standard data analysis method used to search for this background and discuss its detectability with second and third generation networks [...] Read more.
We present the gravitational-wave background and its properties focusing on the background from compact binary coalescences in terrestrial detectors. We also introduce the standard data analysis method used to search for this background and discuss its detectability with second and third generation networks of detectors. To illustrate, we first use simple models and then discuss more realistic models based on simulations. Full article
(This article belongs to the Special Issue Probing the Universe with Gravitational Waves)
►▼ Show Figures

Figure 1

12 pages, 333 KiB  
Article
Nonconservative Unimodular Gravity: Gravitational Waves
by Júlio C. Fabris, Marcelo H. Alvarenga, Mahamadou Hamani Daouda and Hermano Velten
Symmetry 2022, 14(1), 87; https://0-doi-org.brum.beds.ac.uk/10.3390/sym14010087 - 06 Jan 2022
Cited by 5 | Viewed by 1105
Abstract
Unimodular gravity is characterized by an extra condition with respect to general relativity, i.e., the determinant of the metric is constant. This extra condition leads to a more restricted class of invariance by coordinate transformation: The symmetry properties of unimodular gravity are governed [...] Read more.
Unimodular gravity is characterized by an extra condition with respect to general relativity, i.e., the determinant of the metric is constant. This extra condition leads to a more restricted class of invariance by coordinate transformation: The symmetry properties of unimodular gravity are governed by the transverse diffeomorphisms. Nevertheless, if the conservation of the energy–momentum tensor is imposed in unimodular gravity, the general relativity theory is recovered with an additional integration constant which is associated to the cosmological term Λ. However, if the energy–momentum tensor is not conserved separately, a new geometric structure appears with potentially observational signatures. In this text, we consider the evolution of gravitational waves in a nonconservative unimodular gravity, showing how it differs from the usual signatures in the standard model. As our main result, we verify that gravitational waves in the nonconservative version of unimodular gravity are strongly amplified during the evolution of the universe. Full article
(This article belongs to the Special Issue Probing the Universe with Gravitational Waves)
►▼ Show Figures

Figure 1

23 pages, 412 KiB  
Article
Fundamental Gravity and Gravitational Waves
by Riccardo Sturani
Symmetry 2021, 13(12), 2384; https://0-doi-org.brum.beds.ac.uk/10.3390/sym13122384 - 10 Dec 2021
Cited by 6 | Viewed by 1947
Abstract
While being as old as general relativity itself, the gravitational two-body problem has never been under so intense investigation as it is today, spurred by both phenomenological and theoretical motivations. The observations of gravitational waves emitted by compact binary coalescences bear the imprint [...] Read more.
While being as old as general relativity itself, the gravitational two-body problem has never been under so intense investigation as it is today, spurred by both phenomenological and theoretical motivations. The observations of gravitational waves emitted by compact binary coalescences bear the imprint of the source dynamics, and as the sensitivity of detectors improve over years, more accurate modeling is being required. The analytic modeling of classical gravitational dynamics has been enriched in this century by powerful methods borrowed from field theory. Despite being originally developed in the context of fundamental particle quantum scatterings, their applications to classical, bound system problems have shown that many features usually associated with quantum field theory, such as, e.g., divergences and counterterms, renormalization group, loop expansion, and Feynman diagrams, have only to do with field theory, be it quantum or classical. The aim of this work is to present an overview of this approach, which models massive astrophysical objects as nonrelativistic particles and their gravitational interactions via classical field theory, being well aware that while the introductory material in the present article is meant to represent a solid background for newcomers in the field, the results reviewed here will soon become obsolete, as this field is undergoing rapid development. Full article
(This article belongs to the Special Issue Probing the Universe with Gravitational Waves)
►▼ Show Figures

Figure 1

30 pages, 948 KiB  
Article
Mass and Rate of Hierarchical Black Hole Mergers in Young, Globular and Nuclear Star Clusters
by Michela Mapelli, Filippo Santoliquido, Yann Bouffanais, Manuel Arca Sedda, Maria Celeste Artale and Alessandro Ballone
Symmetry 2021, 13(9), 1678; https://0-doi-org.brum.beds.ac.uk/10.3390/sym13091678 - 12 Sep 2021
Cited by 64 | Viewed by 3471
Abstract
Hierarchical mergers are one of the distinctive signatures of binary black hole (BBH) formation through dynamical evolution. Here, we present a fast semi-analytic approach to simulate hierarchical mergers in nuclear star clusters (NSCs), globular clusters (GCs) and young star clusters (YSCs). Hierarchical mergers [...] Read more.
Hierarchical mergers are one of the distinctive signatures of binary black hole (BBH) formation through dynamical evolution. Here, we present a fast semi-analytic approach to simulate hierarchical mergers in nuclear star clusters (NSCs), globular clusters (GCs) and young star clusters (YSCs). Hierarchical mergers are more common in NSCs than they are in both GCs and YSCs because of the different escape velocity. The mass distribution of hierarchical BBHs strongly depends on the properties of first-generation BBHs, such as their progenitor’s metallicity. In our fiducial model, we form black holes (BHs) with masses up to ∼103 M⊙ in NSCs and up to ∼102 M⊙ in both GCs and YSCs. When escape velocities in excess of 100 km s−1 are considered, BHs with mass >103 M⊙ are allowed to form in NSCs. Hierarchical mergers lead to the formation of BHs in the pair instability mass gap and intermediate-mass BHs, but only in metal-poor environments. The local BBH merger rate in our models ranges from ∼10 to ∼60 Gpc−3 yr−1; hierarchical BBHs in NSCs account for ∼10−2–0.2 Gpc−3 yr−1, with a strong upper limit of ∼10 Gpc−3 yr−1. When comparing our models with the second gravitational-wave transient catalog, we find that multiple formation channels are favored to reproduce the observed BBH population. Full article
(This article belongs to the Special Issue Probing the Universe with Gravitational Waves)
►▼ Show Figures

Figure 1

Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:
 
Displaying articles 1-5
Back to TopTop