@article{be778e1fd0344991ab59667087ad8674,
title = "Challenges and opportunities of gravitational-wave searches at MHz to GHz frequencies",
abstract = "The first direct measurement of gravitational waves by the LIGO and Virgo collaborations has opened up new avenues to explore our Universe. This white paper outlines the challenges and gains expected in gravitational-wave searches at frequencies above the LIGO/Virgo band, with a particular focus on Ultra High-Frequency Gravitational Waves (UHF-GWs), covering the MHz to GHz range. The absence of known astrophysical sources in this frequency range provides a unique opportunity to discover physics beyond the Standard Model operating both in the early and late Universe, and we highlight some of the most promising gravitational sources. We review several detector concepts that have been proposed to take up this challenge, and compare their expected sensitivity with the signal strength predicted in various models. This report is the summary of the workshop {"}Challenges and opportunities of high-frequency gravitational wave detection{"} held at ICTP Trieste, Italy in October 2019, that set up the stage for the recently launched Ultra-High-Frequency Gravitational Wave (UHF-GW) initiative.",
keywords = "Ultra-high-frequency gravitational waves, Cosmological gravitational waves, Gravitational wave detectors, Fundamental physics with gavitational waves, PHOTON-GRAVITON CONVERSION, ELECTROMAGNETIC DETECTOR, BUBBLE-GROWTH, FALSE VACUUM, RADIATION, CONSTRAINTS, SENSITIVITY, NUCLEATION, RESONANCE, DECAY",
author = "N. Aggarwal and O.D. Aguiar and A. Bauswein and G. Cella and S. Clesse and A.M. Cruise and V. Domcke and D.G. Figueroa and A. Geraci and M. Goryachev and H. Grote and M. Hindmarsh and F. Muia and N. Mukund and D. Ottaway and M. Peloso and F. Quevedo and A. Ricciardone and J. Steinlechner and S. Steinlechner and S.C. Sun and M.E. Tobar and F. Torrenti and C. Unal and G. White",
note = "Funding Information: We thank all the ICTP staff for providing the excellent conditions that allowed us to organise this workshop, especially to Nadia van Buuren for her efficient and friendly administrative support. Moreover, we thank Ken-Ichi Herada, Sotatsu Otabe, Seyed Mohammad Sadegh Movahed, and Masha Baryakhtar for valuable input. We also thank the two referees of Living Reviews in Relativity for their supportive and well-thought reports. The Australian High-Frequency Gravitational Wave Effort is supported by the Australian Research Council Centre of Excellence for Gravitational Wave Discovery (OzGrav), Grant number CE170100004. N.A. is supported by NSF grant PHY-1806671 and a CIERA Postdoctoral Fellowship from the Center for Interdisciplinary Exploration and Research in Astrophysics at Northwestern University. A.B. acknowledges support by the European Research Council (ERC) under the European Union{\textquoteright}s Horizon 2020 research and innovation programme under grant agreement No. 759253 and by Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) - Project-ID 279384907 - SFB 1245 and - Project-ID 138713538 - SFB 881 ({\textquoteleft}The Milky Way System{\textquoteright}, subproject A10). O.D.A. thanks FAPESP/Brazil (grant numbers 1998/13468-9 and 2006/56041-3) and CNPq/Brazil (grants numbers 306467_2003_8, 303310_2009-0, 307176_2013-4, and 302841/2017-2). This project has received funding from the Deutsche Forschungsgemeinschaft under Germany{\textquoteright}s Excellence Strategy – EXC 2121 {\textquoteleft}Quantum Universe{\textquoteright} – 390833306 (V. D., F. M.). D.G.F. (ORCID 0000-0002-4005-8915) is supported by a Ram{\'o}n y Cajal contract by Spanish Ministry MINECO, with Ref. RYC-2017-23493, and by the grant {\textquoteleft}SOM: Sabor y Origen de la Materia{\textquoteright}, from Spanish Ministry of Science and Innovation, under no. FPA2017-85985-P. A.G. is supported in part by NSF grants PHY-1806686 and PHY-1806671, the Heising-Simons Foundation, the W.M. Keck Foundation, the John Templeton Foundation, and ONR Grant N00014-18-1-2370. M.G. and M.E.T. were funded by the ARC Centre for Excellence for Engineered Quantum Systems, CE170100009, and the ARC Centre for Excellence for Dark Matter Particle Physics, CE200100008, as well as ARC grant DP190100071. F.M. is funded by a UKRI/EPSRC Stephen Hawking fellowship, grant reference EP/T017279/1. This work has been partially supported by STFC consolidated grant ST/P000681/1. A.R. acknowledges funding from Italian Ministry of Education, University and Research (MIUR) through the {\textquoteleft}Dipartimenti di eccellenza{\textquoteright} project Science of the Universe. S.S. was supported by MIUR in Italy under Contract(No. PRIN 2015P5SBHT) and ERC Ideas Advanced Grant (No. 267985) {\textquoteleft}DaMeSyFla{\textquoteright}. F.T. acknowledges support from the Swiss National Science Foundation (project number 200020/175502). C.U. is supported by European Structural and Investment Funds and the Czech Ministry of Education, Youth and Sports (Project CoGraDS - CZ.02.1.01/0.0/0.0/15_003/0000437) and partially supported by ICTP. Publisher Copyright: {\textcopyright} 2021, The Author(s).",
year = "2021",
month = dec,
day = "1",
doi = "10.1007/s41114-021-00032-5",
language = "English",
volume = "24",
journal = "Living Reviews in Relativity",
issn = "2367-3613",
publisher = "Albert Einstein Institut",
number = "1",
}