Related papers: Primordial observables of explicit diffeomorphism …
Gravitational wave astronomy presents a promising opportunity to directly observe scalar-induced gravitational waves originating from the early universe. Experiments, including ground-based interferometers like LIGO and Virgo, and the…
The scalar-induced gravitational waves (SIGW), arising from large amplitude primordial density fluctuations, provide a unique observational test for directly probing the epoch of inflation. In this work, we provide constraints on the SIGW…
Certain alternative theories of gravity predict that gravitational waves will disperse as they travel from the source to the observer. The recent binary black hole observations by Advanced-LIGO have set limits on a modified dispersion…
We propose a novel cosmological probe of dark matter (DM) through inflationary primordial gravitational wave (GW) measurements highlighting its complementarity with traditional indirect detection. In scenarios like early matter domination…
Inspiraling binary neutron stars are expected to be one of the most significant sources of gravitational-wave signals for the new generation of advanced ground-based detectors. We investigate how well we could hope to measure properties of…
GEO 600, Kagra, LIGO, and Virgo were built to observe gravitational waves at frequencies in the audio band, where the highest event rates combined with the largest signal to noise ratios had been predicted. Currently, hypothetical sources…
We study the prospects of future gravitational wave (GW) detectors in probing primordial black hole (PBH) binaries. We show that across a broad mass range from $10^{-5}M_\odot$ to $10^7M_\odot$, future GW interferometers provide a potential…
We study the propagation of cosmological gravitational wave (GW) backgrounds from the early radiation era until the present day in modified theories of gravity. Comparing to general relativity (GR), we study the effects that modified…
The detection of gravitational waves with Advanced LIGO and Advanced Virgo has enabled novel tests of general relativity, including direct study of the polarization of gravitational waves. While general relativity allows for only two tensor…
Accurate modeling of gravitational-wave signals is essential for reliable inference of compact-binary source parameters, particularly for future space-based detectors operating in the milli- and deci-Hertz bands. In this work, we…
Primordial gravitational waves (PGW) produced during inflation span a large range of frequencies, carrying information on the dynamics of the primordial universe. During an early scalar-tensor dominated epoch, the amplitude of the PGW…
This paper is the third in a series of theorems which state how cosmological observations can provide evidence for an early phase of acceleration in the universe. Previous theorems demonstrated that the observed power spectrum for scalar…
Gravitational waves constitute a powerful probe of the underlying theory of gravity. In extensions of general relativity, additional degrees of freedom, such as scalar fields in the gravitational sector, can modify their propagation through…
Dyson (2013) argued that the extraordinarily large number of gravitons in a gravitational wave makes them impossible to be resolved as individual particles. While true, it is shown in this paper that a LIGO interferometric detector also…
It is believed that there are extra fundamental gauge symmetries beyond these described by the Standard Model of particle physics. The scale of these new gauge symmetries are usually too high to be reachable by particle colliders.…
Motivated by the first detection of gravitational waves, this dissertation develops analytical, numerical, and data analysis techniques to address persistent blind spots in our understanding of gravity. Beginning with asymptotically flat…
We survey the prospective sensitivities of terrestrial and space-borne atom interferometers (AIs) to gravitational waves (GWs) generated by cosmological and astrophysical sources, and to ultralight dark matter. We discuss the backgrounds…
The recent detection of a stochastic gravitational wave background by pulsar timing arrays has opened a new window in understanding supermassive black hole binaries and in probing the universe at the early time. Recently, pulsar timing…
We place direct upper limits on the amplitude of gravitational waves from 28 isolated radio pulsars by a coherent multi-detector analysis of the data collected during the second science run of the LIGO interferometric detectors. These are…
Primordial black holes of planetary masses captured by compact stars are widely studied to constrain their composition fraction of dark matter. Such a capture may lead to an inspiral process and be detected through gravitational wave…