Gertsenshtein-Zel$'$dovich effect explains the origin of Fast Radio Bursts

Kushwaha, Ashu; Malik, Sunil; Shankaranarayanan, S.

doi:10.48550/arxiv.2202.00032

Cited by 2 publications

(2 citation statements)

References 36 publications

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“…For instance, the GWs that we receive on Earth have the energy of the order of 10 20 Jansky [5]. Recently, it was shown that the energy carried by GWs could have observable effects like in Fast Radio Bursts [133].…”

Section: Future Outlookmentioning

confidence: 99%

Modified theories of Gravity: Why, How and What?

Shankaranarayanan,

Johnson

2022

Preprint

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General Relativity (GR) was proven via the direct detection of gravitational waves from the mergers of the binary black holes and binary neutron stars by the Advanced LIGO and Advanced Virgo detectors. These detections confirmed the prediction of GR and provided the first direct evidence of the existence of stellar-mass black holes (BHs). However, the occurrence of singularities at the centers of BHs suggests that GR is inapplicable because of the breakdown of the equivalence principle at the singularities. The fact that these singularities exist indicates that GR cannot be a universal theory of space-time. In the low-energy limit, the theoretical and observational challenges faced by the ΛCDM model also indicate that we might have to look beyond GR as the underlying theory of gravity. Unlike GR, whose field equations contain only up to second-order derivatives, the modified theories with higher derivative Ricci/Riemann tensor gravity models include higher derivatives. Therefore, one expects significant differences between GR and modified theories. Since there are many ways of modifying GR in the strong-gravity and cosmological distances, each model has unique features. This leads to the following crucial question: Are there a set of unique signatures that distinguish GR from modified gravity (MG) theories? This review discusses three aspects of MG theories: (1) Why do we need to consider MG theories? (2) How to modify GR? and (3) What are the observational consequences? The review is written in a pedagogical style with the expectation that it will serve as a useful reference for theorists and observers and those interested in bridging the divide between theory and observations.

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Section: Future Outlookmentioning

confidence: 99%

Modified theories of Gravity: Why, How and What?

Shankaranarayanan,

Johnson

2022

Preprint

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“…We provide this reach for the purpose of illustration only; clearly a lot of work needs to be done to probe ultra high-frequency GWs. In additional to the laboratory searches for high-frequency GWs using the inverse Gertsenshtein effect, astrophysical observations of converted electromagnetic signals are also studied in[68,69].…”

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confidence: 99%

Baryogenesis, primordial black holes and MHz–GHz gravitational waves

Gehrman

Haghi

Sinha

et al. 2023

J. Cosmol. Astropart. Phys.

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Gravitational waves (GWs) in the MHz–GHz frequency range are motivated by a host of early Universe phenomena such as oscillons, preheating, and cosmic strings. We point out that baryogenesis too serves as a motivation to probe GWs in this frequency range. The connection is through primordial black holes (PBHs): on the one hand, PBHs induce baryogenesis by Hawking evaporating into a species that has baryon number and CP violating decays; on the other, PBHs induce GWs through second order effects when the scalar fluctuations responsible for their formation re-enter the horizon. We describe the interplay of the parameters responsible for successful baryogenesis on the plane of the strain and frequency of the induced GWs, being careful to delineate regimes where PBH domination or washout effects occur. We provide semi-analytic scalings of the GW strain with the baryon number to entropy ratio and other parameters important for baryogenesis. Along the way, we sketch a solution to the dark matter-baryogenesis coincidence problem with two populations of PBHs, which leads to a double-peaked GW signal. Our results underscore the importance of probing the ultra high frequency GW frontier.

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Gertsenshtein-Zel$'$dovich effect explains the origin of Fast Radio Bursts

Cited by 2 publications

References 36 publications

Modified theories of Gravity: Why, How and What?

Modified theories of Gravity: Why, How and What?

Baryogenesis, primordial black holes and MHz–GHz gravitational waves

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