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Related papers: Scalar-Induced Gravitational Waves in Modified Gra…

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The stochastic gravitational wave background (SGWB) offers a new opportunity to observe signals of primordial features from inflationary models. We study their detectability with future space-based gravitational waves experiments, focusing…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-17 Matteo Braglia , Xingang Chen , Dhiraj Kumar Hazra

In this letter we calculate the scalar induced gravitational waves (SIGWs) accompanying the formation of primordial black hole during the radiation dominated era in three different gauges, i.e. synchronous gauge, Newton gauge and uniform…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-28 Chen Yuan , Zu-Cheng Chen , Qing-Guo Huang

The scalar induced gravitational waves (SIGWs) is a useful tool to probe the physics in the early universe. To study inflationary models with this tool, we need to know how the waveform of SIGWs is related to the shape of the scalar power…

General Relativity and Quantum Cosmology · Physics 2020-09-01 Fengge Zhang , Arshad Ali , Yungui Gong , Jiong Lin , Yizhou Lu

Compared to primordial perturbations on large scales, roughly larger than $1$ megaparsec, those on smaller scales are not severely constrained. We revisit the issue of probing small-scale primordial perturbations using gravitational waves…

Cosmology and Nongalactic Astrophysics · Physics 2019-02-20 Keisuke Inomata , Tomohiro Nakama

Scalar-induced gravitational waves (SIGWs) provide a powerful probe of inflationary dynamics on scales far smaller than those accessible to the cosmic microwave background and large-scale structure. In scenarios with a transient…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-07 Angelo Caravano , Gabriele Franciolini , Sébastien Renaux-Petel

In June 2023, multiple pulsar timing array (PTA) collaborations provided evidence for the existence of a stochastic gravitational-wave background (SGWB). As a significant source of the SGWBs, scalar-induced gravitational waves (SIGWs)…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-26 Yu-Ting Kuang , Jing-Zhi Zhou , Zhe Chang , Di Wu

Gravitational wave (GW) radiations from numerous cosmic stellar-compact-binaries form a stochastic GW background (GWB), which is expected to be detected by ground and space GW detectors in future. Theoretical predictions of this GWB were…

High Energy Astrophysical Phenomena · Physics 2020-11-25 Yuetong Zhao , Youjun Lu

We study the properties of the stochastic gravitational wave background (SGWB) produced by domain walls (DWs) during inflation without forming a network. We numerically simulate the DW production caused by a second-order phase transition…

High Energy Physics - Phenomenology · Physics 2023-04-06 Haipeng An , Chen Yang

We investigate the impact of statistical inhomogeneity and anisotropy in primordial scalar perturbations on the scalar-induced gravitational waves (SIGW). Assuming inflationary quantum fluctuations originate from a coherent state, the…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-08 Dipayan Mukherjee , H. V. Ragavendra , Shiv K. Sethi

Primordial scalar perturbations that reenter the horizon after inflation may induce a second-order Gravitational Wave spectrum with information about the primordial Universe on scales inaccessible to Cosmic Microwave Background experiments.…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-16 Samuel Sánchez López , José Jaime Terente Díaz

Pulsar Timing Arrays are playing a crucial role in the ongoing gravitational wave astronomy revolution. The current evidence for a stochastic gravitational wave background (SGWB) at nHz frequencies offers an opportunity to discover…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-07 Chiara Cecchini , Gabriele Franciolini , Mauro Pieroni

We search for isotropic stochastic gravitational-wave background (SGWB) in the International Pulsar Timing Array second data release. By modeling the SGWB as a power-law, we find very strong Bayesian evidence for a common-spectrum process,…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-28 Zu-Cheng Chen , Yu-Mei Wu , Qing-Guo Huang

Parity-violation leaves tell-tale trails in many cosmological observables. We illustrate parity-odd primordial scalar trispectra, that despite being of modest strength, impart detectable chirality to scalar-induced gravitational waves…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-08 H. V. Ragavendra , Nicola Bartolo

This paper discusses the gauge issue touching the gravitational waves induced at the second order by the scalar modes of cosmological perturbations. These waves are known to depend on the gauge used for their calculation. In this paper, we…

General Relativity and Quantum Cosmology · Physics 2023-09-27 Vincent Comeau

We make forecasts for the impact a future "midband" space-based gravitational wave experiment, most sensitive to $10^{-2}- 10$ Hz, could have on potential detections of cosmological stochastic gravitational wave backgrounds (SGWBs).…

General Relativity and Quantum Cosmology · Physics 2021-06-30 Barry C. Barish , Simeon Bird , Yanou Cui

Gravitational waves (GWs) can undoubtedly serve as a messenger from the early Universe acting as well as a novel probe of the underlying gravity theory. In this work, motivated by one-loop vacuum-polarization effects on curved spacetime, we…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-02 Theodoros Papanikolaou , Charalampos Tzerefos , Salvatore Capozziello , Gaetano Lambiase

We study the induced primordial gravitational waves (GW) coming from the effect of scalar perturbation on the tensor perturbation at the second order of cosmological perturbation theory. We use the evolution of the standard model degrees of…

High Energy Physics - Phenomenology · Physics 2020-02-19 Fazlollah Hajkarim , Jürgen Schaffner-Bielich

In this work, we develop a generic formalism for the study of tensor perturbations induced at second order by first-order vector metric perturbations, dubbing these induced tensor modes $\textit{vector-induced gravitational waves}$ (VIGWs).…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-29 Arko Bhaumik , Theodoros Papanikolaou , Anish Ghoshal

A successful measurement of the Stochastic Gravitational Wave Background (SGWB) in Pulsar Timing Arrays (PTAs) would open up a new window through which to test the predictions of General Relativity (GR). We consider how these measurements…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-29 Qiuyue Liang , Meng-Xiang Lin , Mark Trodden

Gravitational wave (GW) astrophysics is entering a multi-band era with upcoming GW detectors, enabling detailed mapping of the stochastic GW background across vast frequencies. We highlight this potential via a new physics scenario: hybrid…

General Relativity and Quantum Cosmology · Physics 2025-11-26 Yunjia Bao , Tore Boybeyi , Vuk Mandic , Lian-Tao Wang