Abstract Details

Name: Kanhaiya Pandey
Affiliation: International Centre for Theoretical Sciences - TIFR, Bengaluru
Conference ID: ASI2021_477
Title : Constraints on primordial curvature perturbations using LIGO O2 data
Authors and Co-Authors : Shasvath J. Kapadia (ICTS-TIFR, Bengaluru, India), Kanhaiya Lal Pandey (ICTS-TIFR, Bengaluru, India), Teruaki Suyama (Tokyo Institute of Technology, Tokyo, Japan), Shivaraj Kandhasamy (IUCAA, Pune, India), Parameswaran Ajith (ICTS-TIFR, Bengaluru, India)
Abstract Type : Poster
Abstract Category : General Relativity and Cosmology
Abstract : Primordial density perturbations generate a stochastic background of gravitational waves through non-linear mode couplings upon their horizon reentry. For primordial perturbations in the range of comoving wavenumbers 10^16−10^18 Mpc^{−1}, the stochastic gravitational wave background falls within the LIGO detectors' sensitivity band. In this presentation I'll talk about the results of a search for such a stochastic GW background in the data of the two LIGO detectors during their second observing run (O2). In this work we assume a lognormal shape for the power spectrum and Gaussian statistics for the primordial perturbations, and vary the width of the power spectrum to cover both narrow and broad spectra. As a result of this analysis we derive upper limits (95% cl) on the amplitude of the primordial power spectrum for the aforementioned wavenumber range as ~ 0.01−0.1. Also as a byproduct, we are able to infer upper limits on the abundance of the ultralight primordial black holes (M_{PBH} ≃ 10^{−20}−10^{−19} solar mass) at the time of their formation to be ≲10^{−25}. If Hawking evaporation is discarded, this can be translated to constraints on the fraction of dark matter today in the form of such ultralight primordial black holes, which can be as stringent as ~ 10^{−15}−10^{−5}.