Article
Astronomy & Astrophysics
Ogan Ozsoy
Summary: The model based on string theory inspiration can generate gravitational wave signals that satisfy current limits on scalar perturbations at CMB scales. Due to the gravitational coupling of gauge fields and the localized nature of particle production, the characteristics of gravitational wave signals can be probed in future experiments.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Tomohiro Fujita, Kaname Imagawa, Kai Murai
Summary: This study proposes a modified chromo-natural inflation model, which considers the enhanced gravitational wave effect and identifies a parameter space that avoids violating the constraints of cosmic microwave background (CMB) observations.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Ogan Ozsoy
Summary: In this study, we investigate the scalar-tensor-tensor and tensor-scalar-scalar three-point cross-correlations generated by a transiently rolling spectator axion-U(1) gauge field model during inflation. The gravitational couplings between the observable sector and gauge fields can mediate strong correlations between scalar and tensor fluctuations, leading to an amplitude for the mixed-type three-point functions that is larger compared to single-field realizations of inflation. The resulting mixed bispectra are peaked close to the equilateral configurations, with shape dependence, scale dependence, and parity violating nature that can serve as a distinguishing feature of the underlying axion-gauge field dynamics.
Article
Astronomy & Astrophysics
Ogan Ozsoy, Zygmunt Lalak
Summary: The study investigates a mechanism within string theory inspired models of inflation for producing primordial black holes and a gravitational wave background, presenting an example of axion inflation that matches CMB observations and generates a population of light PBHs that can explain dark matter. The resulting GW signal inherits specific properties of its scalar sources, potentially allowing for distinguishing this mechanism from other inflationary scenarios and astrophysical backgrounds.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Rongrong Zhai, Hongwei Yu, Puxun Wu
Summary: This paper investigates the influence of the sound speed and rolling speed on the power spectrum of curvature perturbations during inflation. It is found that a sudden decrease in sound speed leads to a change in the scale dependence of the curvature perturbations and alters the growth trend of the power spectrum. In the model where both sound speed and rolling speed decrease, the power spectrum is nearly scale invariant at large scales and enhanced at small scales, resulting in the formation of primordial black holes. Under certain conditions, the power spectrum can exhibit the steepest growth of k^6.
Article
Astronomy & Astrophysics
Sukannya Bhattacharya, Ivonne Zavala
Summary: Large turns in multifield inflation can lead to a rich phenomenology, but are difficult to realise in supergravity. In this work, a mechanism is presented to realise multiple sharp turns without the requirement of large field space curvatures in supergravity inflation. This mechanism can strongly source adiabatic fluctuations, resulting in an enhanced scalar power spectrum with resonant features and a large peak amplitude. If the scalar power spectrum grows enough at small scales, primordial black holes can be produced in abundance. This model also predicts a large spectrum of gravitational waves with resonant features.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Tomohiro Fujita, Kai Murai, Ippei Obata, Maresuke Shiraishi
Summary: We study the trispectrum of gravitational waves generated during inflation through the dynamics of an axionic spectator field and SU(2) gauge fields. Non-Abelian gauge theory induces four-point self-interactions in gauge fields, resulting in a tree-level trispectrum of gravitational waves. We formulate and evaluate this type of trispectrum, including non-dynamical contributions, in the equilateral limit as a unique signal of this model. We find that the ratio of the trispectrum to the cube of the scalar power spectrum can be as large as O(10(6)) in the viable parameter space, which could be observed in CMB observations.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
P. Klose, M. Laine, S. Procacci
Summary: In this paper, the framework of axion-like inflation is revisited considering the possibility of the inflaton coupling to a non-Abelian topological charge density, which could result in the generation of a rapidly thermalizing heat bath. Both dispersive and absorptive effects are taken into account. It is found that, for phenomenologically viable parameters, the system remains in a weak regime of warm inflation. An interpolating formula for tensor perturbations is derived, which incorporates both vacuum and thermal production. The coefficient in the thermal production yields a model-independent frequency shape similar to f03 in the LISA window, and it can be used to measure the maximal shear viscosity of the thermal epoch. However, finding models with a large enough coefficient to be observable is a challenge.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
P. Klose, M. Laine, S. Procacci
Summary: A study on the interaction between a pseudoscalar inflaton and a non-Abelian sector reveals that this coupling can efficiently heat up the medium through the production of gauge bosons. By analyzing hydrodynamic fluctuations and particle collisions, a lower bound for the production rate of gravitational waves is determined, indicating that non-Abelian models may avoid overproduction.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Jan Hamann, Ameek Malhotra
Summary: This study utilizes temperature and polarization maps from the Planck and BICEP/Keck datasets to search for scale-dependent features in the stochastic background of gravitational waves. The focus is on a log-normal bump in the primordial tensor spectrum at CMB scales. Although no evidence of such features is found currently, future CMB experiments like LiteBIRD and CMB-S4 are expected to greatly improve the ability to determine the amplitude, location, and width of such a bump.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Arshad Ali, Yungui Gong, Yizhou Lu
Summary: The paragraph discusses the results of studying scalar-induced tensor perturbations during matter domination in various gauges, revealing that the kernel functions in synchronous and comoving gauges are the same and identifying oscillating terms in the perturbations as the secondary gravitational waves induced by scalars. Additionally, it is found that the energy density of these waves is gauge independent and behaves like radiation in the matter-dominated era.
Article
Astronomy & Astrophysics
Paolo Campeti, Oegan Ozsoy, Ippei Obata, Maresuke Shiraishi
Summary: In this study, new constraints on spectator axion-U(1) gauge field interactions during inflation are presented using the latest Planck and BICEP/Keck data releases. The observational bounds are found to be competitive with theoretical ones, excluding a significant portion of the parameter space of the model.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Jacopo Fumagalli, Mauro Pieroni, Sebastien Renaux-Petel, Lukas T. Witkowski
Summary: In this study, the detection prospects of oscillations in the frequency profile of the stochastic gravitational wave background are investigated using the upcoming space-based gravitational wave observatory LISA. It is found that the oscillations can be reconstructed with LISA, and it is confirmed that they are a worthwhile target for future detection efforts and offer a key for experimentally testing inflation at small scales.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Diego Santos de Jesus, Hermano Velten, Federico Piazza
Summary: In this paper, we revisit the decay of the orbital period in binary systems caused by the emission of gravitational waves, considering modified gravity models where the coupling Ggw between matter and on shell gravitons differs from the Newton constant GN. By using the double pulsar, the most precisely-timed double neutron star binary system, we constrain the ratio Ggw=GN to the level of 10-4, improving the present bound on this quantity by two orders of magnitude.
Article
Astronomy & Astrophysics
Shaoqi Hou, Xi-Long Fan, Zong-Hong Zhu
Summary: Gravitational lensing can be used to constrain cosmology models through statistical lensing and time delay methods, with potential improvements in measurements tightening constraints on parameters. Estimated events from future interferometers could significantly impact the knowledge of cosmological parameters.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Raphael Flauger, Nikolaos Karnesis, Germano Nardini, Mauro Pieroni, Angelo Ricciardone, Jesus Torrado
Summary: A data analysis methodology was proposed for model-independent reconstruction of the spectral shape of a stochastic gravitational wave background with LISA;
The improved algorithm includes a complete set of TDI channels, reducing uncertainties, avoiding local extrema in likelihood maximization, and breaking degeneracies between signal and instrumental noise;
Testing with case studies showed that additional channels are helpful in various ways for the reconstruction process.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Giorgio Orlando, Mauro Pieroni, Angelo Ricciardone
Summary: This paper explores the possibility of detecting circular polarization of an isotropic Stochastic Gravitational Wave Background by cross-correlating two space-based detectors, LISA and Taiji, and finds that a clear measurement of chirality can be claimed for a maximally chiral flat signal with specific amplitude at the frequency scales of LISA and Taiji.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Multidisciplinary Sciences
Alexei Tkachenko, Sergei Maslov, Ahmed Elbanna, George N. Wong, Zachary J. Weiner, Nigel Goldenfeld
Summary: Research shows that during the early stages of an epidemic, a transient collective immunity state may emerge as herd immunity forms, but this state is fragile and fades over time, meaning that the infection peak does not necessarily indicate long-lasting herd immunity; factors such as seasonal changes can lead to subsequent waves.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Astronomy & Astrophysics
Tessa Baker, Gianluca Calcagni, Anson Chen, Matteo Fasiello, Lucas Lombriser, Katarina Martinovic, Mauro Pieroni, Mairi Sakellariadou, Gianmassimo Tasinato, Daniele Bertacca, Ippocratis D. Saltas
Summary: The possibility of transient deviations of the propagation speed of gravitational waves from the speed of light at low frequencies, based on modifications of General Relativity, is discussed. The impact of these deviations on the gravitational waveforms of black hole binary mergers detectable by the LISA mission is studied. Constraints on these deviations obtainable from individual systems and a population of sources are forecasted.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Jacopo Fumagalli, Mauro Pieroni, Sebastien Renaux-Petel, Lukas T. Witkowski
Summary: In this study, the detection prospects of oscillations in the frequency profile of the stochastic gravitational wave background are investigated using the upcoming space-based gravitational wave observatory LISA. It is found that the oscillations can be reconstructed with LISA, and it is confirmed that they are a worthwhile target for future detection efforts and offer a key for experimentally testing inflation at small scales.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Multidisciplinary Sciences
Mauro Pieroni, Angelo Ricciardone, Enrico Barausse
Summary: We study stellar-origin black hole binaries, which are important astrophysical sources for next generation gravitational wave detectors. Through population models and analysis of recent results, we find that these detectors will be able to detect tens of thousands of sources and accurately estimate the parameters of the binaries.
SCIENTIFIC REPORTS
(2022)
Article
Astronomy & Astrophysics
Nicola Bartolo, Daniele Bertacca, Robert Caldwell, Carlo R. Contaldi, Giulia Cusin, Valerio De Luca, Emanuela Dimastrogiovanni, Matteo Fasiello, Daniel G. Figueroa, Gabriele Franciolini, Alexander C. Jenkins, Marco Peloso, Mauro Pieroni, Arianna Renzini, Angelo Ricciardone, Antonio Riotto, Mairi Sakellariadou, Lorenzo Sorbo, Gianmassimo Tasinato, Jesus Torrado, Sebastien Clesse, Sachiko Kuroyanagi
Summary: We investigate the sensitivity of the Laser Interferometer Space Antenna (LISA) to the anisotropies of the Stochastic Gravitational Wave Background (SGWB). By building a Signal-to-Noise estimator and performing a Fisher matrix analysis, we quantify the detectability of different multipoles by LISA. This study provides important information for understanding the origin of the SGWB and discriminating among different superimposed SGWB sources.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Maria Georgousi, Nikolaos Karnesis, Valeriya Korol, Mauro Pieroni, Nikolaos Stergioulas
Summary: Future gravitational wave detectors like LISA will be able to resolve a significant number of ultra compact stellar-mass binaries, mostly double white dwarfs, and directly correlate their characteristics to the properties of the Galaxy. By investigating the spectral shape and amplitude of the confusion foreground signal, a framework is proposed to infer the total stellar mass. Simulations of LISA data show that the DWD frequency, coalescence time, and chirp mass distributions can be reconstructed without bias.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Tessa Baker, Enrico Barausse, Anson Chen, Claudia de Rham, Mauro Pieroni, Gianmassim Tasinto
Summary: Effective field theories (EFT) of dark energy (DE) are limited by constraints on the propagation speed of gravitational waves (GW) but can still be valid at scales beyond the EFT description. Lower frequency observations by LISA would be harder to escape, while a joint observation by LISA and a terrestrial interferometer could constrain the speed of light and gravitons to within 10^-15. Multiband GW observations can therefore effectively constrain DE scenarios based on EFT.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Marilena Loverde, Zachary J. Weiner
Summary: We study the modulation of the standard damping of gravitational waves by free-streaming radiation due to the decoupling (or recoupling) of interactions. We focus on nonstandard neutrino interactions in effect after the decoupling of weak interactions as well as more general scenarios in the early Universe involving other light relics. Finally, we compute the imprint of neutrino interactions on the B-mode polarization of the cosmic microwave background, and we comment on other means to infer the presence of such effects at higher frequencies.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Marica Branchesi, Michele Maggiore, David Alonso, Charles Badger, Biswajit Banerjee, Freija Beirnaert, Enis Belgacem, Swetha Bhagwat, Guillaume Boileau, Ssohrab Borhanian, Daniel David Brown, Man Leong Chan, Giulia Cusin, Stefan L. Danilishin, Jerome Degallaix, Valerio De Luca, Arnab Dhani, Tim Dietrich, Ulyana Dupletsa, Stefano Foffa, Gabriele Franciolini, Andreas Freise, Gianluca Gemme, Boris Goncharov, Archisman Ghosh, Francesca Gulminelli, Ish Gupta, Pawan Kumar Gupta, Jan Harms, Nandini Hazra, Stefan Hild, Tanja Hinderer, Ik Siong Heng, Francesco Iacovelli, Justin Janquart, Kamiel Janssens, Alexander C. Jenkins, Chinmay Kalaghatgi, Xhesika Koroveshi, Tjonnie G. F. Li, Yufeng Li, Eleonora Loffredo, Elisa Maggio, Michele Mancarella, Michela Mapelli, Katarina Martinovic, Andrea Maselli, Patrick Meyers, Andrew L. Miller, Chiranjib Mondal, Niccolo Muttoni, Harsh Narola, Micaela Oertel, Gor Oganesyan, Costantino Pacilio, Cristiano Palomba, Paolo Pani, Antonio Pasqualetti, Albino Perego, Carole Perigois, Mauro Pieroni, Ornella Juliana Piccinni, Anna Puecher, Paola Puppo, Angelo Ricciardone, Antonio Riotto, Samuele Ronchini, Mairi Sakellariadou, Anuradha Samajdar, Filippo Santoliquido, B. S. Sathyaprakash, Jessica Steinlechner, Sebastian Steinlechner, Andrei Utina, Chris Van Den Broeck, Teng Zhang
Summary: This study evaluates the scientific prospects of the Einstein Telescope, comparing the results of a triangular configuration and a network of two L-shaped detectors under varying parameters. It also examines the impact of lacking a low-frequency instrument on the scientific output for both configurations, and analyzes specific scientific objectives.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Mary Gerhardinger, John T. Jr Jr Giblin, Andrew J. Tolley, Mark Trodden
Summary: The Galileon scalar field theory, which exhibits the Vainshtein screening mechanism, has implications for predictions of gravitational waves and tests of gravity. The derivative nature of their interactions poses a challenge in effective field theories but can be overcome through numerical simulations.
Article
Astronomy & Astrophysics
David Cyncynates, Olivier Simon, Jedidiah O. Thompson, Zachary J. Weiner
Summary: Pairs of misalignment-produced axions can undergo nonlinear resonance, enhancing the direct and astrophysical signatures of axion dark matter. Nonlinear dynamics can equilibrate the abundance of the axion pairs, making it easier to experimentally confirm their existence. Additionally, the gravitational wave emission and polarization of the cosmic microwave background provide constraints on the properties of friendly axion dark matter.
Article
Astronomy & Astrophysics
Daniel G. Figueroa, Adrien Florio, Nicolas Loayza, Mauro Pieroni
Summary: This paper discusses the possibility of measuring particle couplings using stochastic gravitational wave backgrounds (SGWBs). It is found that a sequence of stair-like peaks, with each peak probing a different coupling, can emerge in the SGWB spectrum. By detecting this signature, it is possible to reconstruct the couplings of the particle species involved in high energy phenomena that generate SGWBs. Stair-like signatures may arise in causally produced backgrounds in the early Universe.
Article
Astronomy & Astrophysics
Nikolaos Karnesis, Stanislav Babak, Mauro Pieroni, Neil Cornish, Tyson Littenberg
Summary: This study presents a generic method for characterizing foreground signals from a given astrophysical population and predicts different levels of foreground noise through an iterative procedure.