A5034257635- Pulsars and Gravitational Waves Research
- Cosmology and Gravitation Theories
- Black Holes and Theoretical Physics
- Astrophysical Phenomena and Observations
- Geophysics and Gravity Measurements
- Gamma-ray bursts and supernovae
- Relativity and Gravitational Theory
- Geophysics and Sensor Technology
- High-pressure geophysics and materials
- Noncommutative and Quantum Gravity Theories
- Astrophysics and Cosmic Phenomena
- Atomic and Subatomic Physics Research
- High-Energy Particle Collisions Research
- Seismic Waves and Analysis
- Computational Physics and Python Applications
- Radio Astronomy Observations and Technology
- Stellar, planetary, and galactic studies
- Superconducting Materials and Applications
- Astro and Planetary Science
- Adaptive optics and wavefront sensing
- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- Quantum, superfluid, helium dynamics
- Astronomy and Astrophysical Research
- Solar and Space Plasma Dynamics
University of Illinois Urbana-Champaign
2019-2025
Kent State University
2023
Campbell Collaboration
2023
Montana State University
2012-2021
University of Vienna
2020
Fudan University
2019
Princeton University
2009-2016
University of California, Santa Barbara
2015-2016
Massachusetts Institute of Technology
2011-2012
Kavli Institute for Particle Astrophysics and Cosmology
2012
The gravitational wave observations GW150914 and GW151226 by Advanced LIGO provide the first opportunity to learn about physics in extreme gravity environment of coalescing binary black holes. Scientific Collaboration Virgo have verified that this observation is consistent with General Relativity. This paper expands their analysis a larger class anomalies, highlighting inferences can be drawn on non-standard theoretical mechanisms. We find these events constrain plethora mechanisms...
The exterior gravitational field of a slowly rotating neutron star can be characterized by its multipole moments, the first few being mass, moment inertia, and quadrupole to quadratic order in spin. In principle, all these quantities depend on star's internal structure, thus, unknown nuclear physics at supranuclear energy densities, which is usually parametrized through an equation state. We here find relations between Love numbers (I-Love-Q relations) that do not sensitively structure. Such...
Neutron stars and quark are not only characterized by their mass radius but also how fast they spin, through moment of inertia, much can be deformed, Love number quadrupole moment. These depend sensitively on the star's internal structure thus unknown nuclear physics. We find universal relations between number, that independent neutron structure. used to learn about star deformability observations break degeneracies in gravitational wave detection measure spin binary inspirals, distinguish...
We consider the concept of fundamental bias in gravitational wave astrophysics as assumption that general relativity is correct theory gravity during entire wave-generation and propagation regime. Such an valid weak field, verified by precision experiments observations, but it need not hold dynamical strong-field regime where tests are lacking. Fundamental can cause systematic errors detection parameter estimation signals, which lead to a mischaracterization Universe through incorrect...
The low-energy limit of string theory contains an anomaly-canceling correction to the Einstein-Hilbert action, which defines effective theory: Chern-Simons (CS) modified gravity. CS consists product a scalar field with Pontryagin density, where former can be treated as background (nondynamical formulation) or evolving (dynamical formulation). Many solutions general relativity persist in theory; notable exception is Kerr metric, has sparked search for rotating black hole solutions. Here,...
We study the secular, hierarchical three-body problem to first-order in a post-Newtonian expansion of General Relativity. expand Hamiltonian leading-order ratio semi-major axis two orbits. In addition well-known terms that correspond GR precession inner and outer orbits, we find new secular interaction term can affect long-term evolution triple. explore parameter space for highly inclined eccentric systems, where Kozai-Lidov mechanism produce large-amplitude oscillations eccentricities. The...
We study two large classes of alternative theories, modifying the action through algebraic, quadratic curvature invariants coupled to scalar fields. find one class that admits solutions solve vacuum Einstein equations and another does not. In latter, we a deformation Schwarzschild metric solves modified field in small coupling approximation. calculate event horizon shift, innermost stable circular orbit corrections gravitational waves, mapping them parametrized post-Einsteinian framework.
The Laser Interferometer Space Antenna (LISA) has the potential to reveal wonders about fundamental theory of nature at play in extreme gravity regime, where gravitational interaction is both strong and dynamical. In this white paper, Fundamental Physics Working Group LISA Consortium summarizes current topics physics observations GWs can be expected provide key input. We briefest reviews then delineate avenues for future research directions discuss connections between working group, other...
We derive a stationary and axisymmetric black hole solution in Einstein-Dilaton-Gauss-Bonnet gravity to quadratic order the ratio of spin angular momentum mass squared. This introduces new corrections previously found nonspinning linear-in-spin solutions. The location event horizon ergosphere are modified, as well quadrupole moment. is Petrov type I, although lower solutions D. There no closed timelike curves or spacetime regions that violate causality outside solution. calculate...
Binary pulsars are ideal to test the foundations of General Relativity, such as Lorentz symmetry, which requires that experiments produce same results in all free-falling (i.e.inertial) frames. We here break this symmetry gravitational sector by specifying a preferred time direction, and thus frame, at each spacetime point. then examine consequences breaking orbital evolution binary pulsars, focusing on dissipative effects. find modifies these effects, dynamics, two different ways. First, it...
It was recently shown that a scalar field suitably coupled to the Gauss-Bonnet invariant $\mathcal{G}$ can undergo spin-induced linear tachyonic instability near Kerr black hole. This appears only once dimensionless spin $j$ is sufficiently large, is, $j \gtrsim 0.5$. A hallmark of spontaneous scalarization. Focusing, for illustrative purposes, on class theories do exhibit this instability, we show stationary, rotating hole solutions indeed have hair threshold exceeded, while holes lie below...
The aLIGO detection of the black-hole binary GW150914 opens a new era for probing extreme gravity. Many gravity theories predict emission dipole gravitational radiation by binaries. This is excluded to high accuracy in pulsars, but entire classes this effect predominantly (or only) binaries involving black holes. Joint observations GW150914-like systems and eLISA will improve bounds on from 6 orders magnitude relative current constraints, provided that not dramatically descoped.
Gravitational-wave astronomy offers not only new vistas into the realm of astrophysics, but it also opens an avenue for probing, first time, general relativity in its strong-field, nonlinear, and dynamical regime, where theory's predictions manifest themselves their full glory. We present a study whether gravitational-wave events detected so far by LIGO-Virgo scientific collaborations can be used to probe higher-curvature corrections relativity. In particular, we focus on two examples:...
Gravitational wave observations of compact binaries allow us to test general relativity (and modifications thereof) in the strong and highly-dynamical field regime gravity. Here we confront two extensions relativity, dynamical Chern-Simons Einstein-dilaton-Gauss-Bonnet theories, against gravitational sources from GWTC-1 GWTC-2 catalogs by LIGO-Virgo Collaboration. By stacking posterior individual events, strengthen constraint on square root coupling parameter gravity $\sqrt{\alpha_{\rm \tiny...
The detection of gravitational waves from compact binary mergers by the LIGO/Virgo collaboration has, for first time, allowed tests relativistic gravity in strong, dynamical and nonlinear regime. Outside Einstein's relativity, spinning black holes may be different their general counterparts, merger then lead to a modified ringdown. We study latter and, derive Teukolsky equation, i.e., set linear, decoupled differential equations that describe perturbations non-Kerr radiative Newman-Penrose...
Abstract This review aims at providing an extensive discussion of modern constraints relevant for dense and hot strongly interacting matter. It includes theoretical first-principle results from lattice perturbative QCD, as well chiral effective field theory results. From the experimental side, it heavy-ion collision low-energy nuclear physics results, observations neutron stars their mergers. The validity different constraints, concerning specific conditions ranges applicability, is also provided.
The detection of gravitational waves resulting from the coalescence binary black holes by LIGO-Virgo-Kagra Collaboration has inaugurated a new era in physics. These provide unique opportunity to test Einstein’s general relativity and its modifications regime extreme gravity. A significant aspect such tests involves study ringdown phase hole coalescence, which can be decomposed into superposition various quasinormal modes. In relativity, spectra modes depend on mass, spin, charge final hole,...
General relativity (GR) has proven to be a highly successful theory of gravity since its inception. The thrivingly passed numerous experimental tests, predominantly in weak gravity, low relative speeds, and linear regimes, but also the strong-field very low-speed regimes with binary pulsars. Observable gravitational waves (GWs) originate from regions spacetime where is extremely strong, making them unique tool for testing GR, previously inaccessible large curvature, relativistic strong...
We develop a model-independent test of general relativity that allows for the constraint gravitational wave (GW) polarization content with GW detections binary compact object inspirals. first consider three modified gravity theories (Brans-Dicke theory, Rosen's and Lightman-Lee theory) calculate response function ground-based detectors to waves in inspiral phase. This us see how additional polarizations predicted these modify relativistic prediction function. then power-law modifications...
Modified gravity theories generically predict a violation of Lorentz invariance, which may lead to modified dispersion relation for propagating modes gravitational waves. We construct parametrized that can reproduce range known Lorentz-violating predictions and investigate their impact on the propagation A forces different wavelengths gravitational-wave train travel at slightly velocities, leading phase evolution observed detector. show how such corrections map waveform observable...
Gravitational wave astronomy has tremendous potential for studying extreme astrophysical phenomena and exploring fundamental physics. The waves produced by binary black hole mergers will provide a pristine environment in which to study strong field, dynamical gravity. Extracting detailed information about these systems requires accurate theoretical models of the gravitational signals. If gravity is not described General Relativity, analyses that are based on waveforms derived from Einstein's...