Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 5 of 5
Full-Text Articles in Physics
Gw170817: Measurements Of Neutron Star Radii And Equation Of State, B. P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.
Gw170817: Measurements Of Neutron Star Radii And Equation Of State, B. P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.
Physics Faculty Research & Creative Works
On 17 August 2017, the LIGO and Virgo observatories made the first direct detection of gravitational waves from the coalescence of a neutron star binary system. The detection of this gravitational-wave signal, GW170817, offers a novel opportunity to directly probe the properties of matter at the extreme conditions found in the interior of these stars. The initial, minimal-assumption analysis of the LIGO and Virgo data placed constraints on the tidal effects of the coalescing bodies, which were then translated to constraints on neutron star radii. Here, we expand upon previous analyses by working under the hypothesis that both bodies were …
Gravitational Effects In G -Factor Measurements And High-Precision Spectroscopy: Limits Of Einstein's Equivalence Principle, Ulrich D. Jentschura
Gravitational Effects In G -Factor Measurements And High-Precision Spectroscopy: Limits Of Einstein's Equivalence Principle, Ulrich D. Jentschura
Physics Faculty Research & Creative Works
We study the interplay of general relativity, the equivalence principle, and high-precision experiments involving atomic transitions and g-factor measurements. In particular, we derive a generalized Dirac Hamiltonian, which describes both the gravitational coupling for weak fields and the electromagnetic coupling, e.g., to a central Coulomb field. An approximate form of this Hamiltonian is used to derive the leading gravitational corrections to transition frequencies and g factors. The position dependence of atomic transitions is shown to be compatible with the equivalence principle, up to a very good approximation. The compatibility of g-factor measurements requires a deeper subtle analysis in order to …
Search For Tensor, Vector, And Scalar Polarizations In The Stochastic Gravitational-Wave Background, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.
Search For Tensor, Vector, And Scalar Polarizations In The Stochastic Gravitational-Wave Background, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.
Physics Faculty Research & Creative Works
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 gravitational-wave polarizations, general metric theories can additionally predict two vector and two scalar polarizations. The polarization of gravitational waves is encoded in the spectral shape of the stochastic gravitational-wave background, formed by the superposition of cosmological and individually unresolved astrophysical sources. Using data recorded by Advanced LIGO during its first observing run, we search for a stochastic background of generically polarized gravitational waves. We find …
Gw170817: Implications For The Stochastic Gravitational-Wave Background From Compact Binary Coalescences, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.
Gw170817: Implications For The Stochastic Gravitational-Wave Background From Compact Binary Coalescences, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.
Physics Faculty Research & Creative Works
The LIGO Scientific and Virgo Collaborations have announced the event GW170817, the first detection of gravitational waves from the coalescence of two neutron stars. The merger rate of binary neutron stars estimated from this event suggests that distant, unresolvable binary neutron stars create a significant astrophysical stochastic gravitational-wave background. The binary neutron star component will add to the contribution from binary black holes, increasing the amplitude of the total astrophysical background relative to previous expectations. In the Advanced LIGO-Virgo frequency band most sensitive to stochastic backgrounds (near 25 Hz), we predict a total astrophysical background with amplitude ΩGW( …
First Search For Nontensorial Gravitational Waves From Known Pulsars, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.
First Search For Nontensorial Gravitational Waves From Known Pulsars, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.
Physics Faculty Research & Creative Works
We present results from the first directed search for nontensorial gravitational waves. While general relativity allows for tensorial (plus and cross) modes only, a generic metric theory may, in principle, predict waves with up to six different polarizations. This analysis is sensitive to continuous signals of scalar, vector, or tensor polarizations, and does not rely on any specific theory of gravity. After searching data from the first observation run of the advanced LIGO detectors for signals at twice the rotational frequency of 200 known pulsars, we find no evidence of gravitational waves of any polarization. We report the first upper …