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Related papers: Gravitational waves from low-scale cosmic strings

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We study the gravitational radiation from a rotating monopole-antimonopole pair connected by a string. While at not too high frequencies the emitted gravitational spectrum is described asymptotically by $P_n\propto n^{-1}$, the spectrum is…

Astrophysics · Physics 2010-11-19 E. Babichev , V. Dokuchaev , M. Kachelriess

The NANOGrav Collaboration recently reported a strong evidence for a stochastic common-spectrum process in the pulsar-timing data. We evaluate the evidence of interpreting this process as mergers of super massive black hole binaries and/or…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-21 Ligong Bian , Rong-Gen Cai , Jing Liu , Xing-Yu Yang , Ruiyu Zhou

Cosmological gravitational wave backgrounds (CGWBs) are the conglomeration of unresolved gravitational wave signals from early Universe sources, which make them a promising tool for cosmologists. Because gravitons decouple from the cosmic…

General Relativity and Quantum Cosmology · Physics 2023-12-27 Tatsuya Daniel , Marcell Howard , Morgane König

We study future observational constraints on cosmic string parameters from various types of next-generation experiments: direct detection of gravitational waves (GWs), pulsar timing array, and the cosmic microwave background (CMB). We…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-30 Sachiko Kuroyanagi , Koichi Miyamoto , Toyokazu Sekiguchi , Keitaro Takahashi , Joseph Silk

Recently, multiple pulsar timing array collaborations have presented compelling evidence for a stochastic signal at nanohertz frequencies, potentially originating from cosmic strings. Cosmic strings are linear topological defects that can…

Instrumentation and Methods for Astrophysics · Physics 2025-03-28 Zu-Cheng Chen , Qing-Guo Huang , Chang Liu , Lang Liu , Xiao-Jin Liu , You Wu , Yu-Mei Wu , Zhu Yi , Zhi-Qiang You

We study stochastic gravitational waves from cosmic strings generated in an ultraviolet-complete model for pseudo-Nambu-Goldstone dark matter with a hidden $\mathrm{U(1)}$ gauge symmetry. The dark matter candidate in this model can…

High Energy Physics - Phenomenology · Physics 2023-07-11 Ze-Yu Qiu , Zhao-Huan Yu

We describe the detailed study and results of high-resolution numerical simulations of string-induced structure formation in open universes and those with a non-zero cosmological constant. The effect from small loops generated from the…

Astrophysics · Physics 2009-09-25 J. H. P. Wu , P. P. Avelino , E. P. S. Shellard , B. Allen

The precise calculation of gravitational wave (GW) and particle emissions from cosmic string networks is of significant theoretical and experimental interest. In this Letter, we perform numerical simulations of near-global and local string…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-02 Zizhuo Zhao , Ligong Bian , Jing Shu

Recently, pulsar timing array (PTA) experiments have provided compelling evidence for the existence of the nanohertz stochastic gravitational wave background (SGWB). In this work, we demonstrated that cosmic string loops generated from…

High Energy Astrophysical Phenomena · Physics 2023-11-16 Ziwei Wang , Lei Lei , Hao Jiao , Lei Feng , Yi-Zhong Fan

In determining the gravitational signal of cusps from a network of cosmic strings loops, a number of key parameters have to be assumed. These include the typical number of cusps per period of string oscillation and the typical values of the…

High Energy Physics - Theory · Physics 2021-04-07 Despoina Pazouli , Anastasios Avgoustidis , Edmund J. Copeland

Black holes, the simplest solution to Einstein's field equations, do not emit light, making their observations a major challenge for researchers. However, discovery of binary black holes (BBHs) in 2015 by LIGO has transformed the study of…

General Relativity and Quantum Cosmology · Physics 2025-12-10 Ishan Swamy , Deobrat Singh

Gravitational wave (GW) observations are expected to serve as a powerful and independent probe of the expansion history of the universe. By providing direct and calibration-free measurements of luminosity distances through waveform…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-06 Shang-Jie Jin , Ji-Yu Song , Tian-Yang Sun , Si-Ren Xiao , He Wang , Ling-Feng Wang , Jing-Fei Zhang , Xin Zhang

The energy spectrum of gravitational waves (GWs), which depicts the energy of GWs per unit volume of space per logarithmic frequency interval normalized to the critical density of the Universe, is a widely used way for quantifying the…

Cosmology and Nongalactic Astrophysics · Physics 2021-09-15 Rong-Gen Cai , Xing-Yu Yang , Long Zhao

We compute the spectrum of relic gravitons in a model of string cosmology. In the low- and in the high-frequency limits we reproduce known results. The full spectrum, however, also displays a series of oscillations which could give a…

General Relativity and Quantum Cosmology · Physics 2011-09-09 A. Buonanno , M. Maggiore , C. Ungarelli

We develop an analytical model to study the production spectrum of loops in the cosmic string network. In the scaling regime, we find two different scales corresponding to large (one order below horizon) and small (few orders below horizon)…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Vitaly Vanchurin

Primordial gravitational waves (GWs) with frequencies > 10^{-15} Hz contribute to the radiation density of the Universe at the time of decoupling of the cosmic microwave background (CMB). The effects of this GW background on the CMB and…

Astrophysics · Physics 2009-11-11 Tristan L. Smith , Elena Pierpaoli , Marc Kamionkowski

Recently it has been shown that string gas cosmology, an alternative model of the very early universe which does not involve a period of cosmological inflation, can give rise to an almost scale invariant spectrum of metric perturbations.…

High Energy Physics - Theory · Physics 2008-03-05 Bin Chen , Yi Wang , Wei Xue , Robert Brandenberger

We initiate the LISA template databank for stochastic gravitational wave backgrounds sourced by cosmic strings. We include two templates, an analytical template, which enables more flexible searches, and a numerical template derived…

We derive analytical approximations to describe the ultra-high-frequency secondary peak of the stochastic gravitational wave background generated by cosmic strings that is sourced by loops created in the friction-dominated era. We show that…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-25 Sergei Mukovnikov , Lara Sousa

Although cosmic string scenario for galaxy formation is disfavored by CMB data, it is of great interest in the generation of cosmic gravitational-wave background. This research aims to develop an algorithm to extract cosmic…

General Relativity and Quantum Cosmology · Physics 2012-02-20 Alf Tang , Timothy J. Sumner