Related papers: Gravitational radiation from binary systems in Uni…
We consider models of gravitation that are based on unimodular general coordinate transformations (GCT). These transformations include only those which do not change the determinant of the metric. We treat the determinant as a separate…
The explicit violation of the general gauge invariance/relativity is adopted as the origin of dark matter and dark energy of the gravitational nature. The violation of the local scale invariance alone, with the residual unimodular one, is…
Many physically motivated extensions to general relativity (GR) predict significant deviations in the properties of spacetime surrounding massive neutron stars. We report the measurement of a 2.01 +/- 0.04 solar mass pulsar in a 2.46-hr…
The merger phase of compact binary coalescences is the strongest gravity regime that can be observed. To test the validity of general relativity (GR) in strong gravitational fields, we propose a gravitational waveform parameterized for…
The conformal invariance of unimodular gravity survives quantum corrections, even in the presence of conformal matter. Unimodular gravity can actually be understood as a certain truncation of the full Einstein-Hilbert theory, where in the…
Every emission of radiation in gravity also includes a nonwavelike component that leaves a permanent change in proper distances of the spacetime it travels through. This phenomenon is known as gravitational displacement memory. Building up…
We discuss the possibility to obtain an electromagnetic emission accompanying the gravitational waves emitted in the coalescence of a compact binary system. Motivated by the existence of black hole configurations with open magnetic field…
The rate of gravitational-wave energy loss from inspiralling binary systems of compact objects of arbitrary mass is derived through second post-Newtonian (2PN) order $O[(Gm/rc^2)^2]$ beyond the quadrupole approximation. The result has been…
A generalized true anomaly-type parametrization, convenient to describe both bound and open orbits of a two-body system in general relativity is introduced. A complete description of the time evolution of both the radial and of the angular…
This talk reviews the constraints imposed by binary-pulsar data on gravity theories, and notably on "scalar-tensor" theories which are the most natural alternatives to general relativity. Because neutron stars have a strong gravitational…
We discuss unimodular gravity at a classical level, and in terms of its extension into the UV through an appropriate path integral representation. Classically, unimodular gravity is simply a gauge fixed version of General Relativity (GR),…
Unimodular Gravity is normally assumed to be equivalent to General Relativity for all matters but the character of the Cosmological Constant. Here we discuss this equivalence in the presence of a non-minimally coupled scalar field. We show…
We recently suggested a nonlocal modification of Einstein's field equations in which Newton's constant $G$ was promoted to a covariant differential operator $G_\Lambda(\Box_g)$. The latter contains two independent contributions, which…
We show that if the visible universe is a membrane embedded in a higher-dimensional space, particles in uniform motion radiate gravitational waves because of spacetime lumpiness. This phenomenon is analogous to the electromagnetic…
We propose a method to constrain the variation of the gravitational constant $G$ with cosmic time using gravitational-wave (GW) observations of merging binary neutron stars. The method essentially relies on the fact that the maximum and…
In order to investigate the gravitational wave (GW) radiation, without appealing to the tensorial formalism of the linearized general relativity, we formulate the so-called modified linearized general relativity (MLGR). As an application of…
We study cosmological perturbation theory within the framework of unimodular gravity. We show that the Lagrangian constraint on the determinant of the metric required by unimodular gravity leads to an extra constraint on the gauge freedom…
We work out the one-loop and order $\kappa^2 m_\phi^2$ UV divergent contributions, coming from Unimodular Gravity and General Relativity, to the S matrix element of the scattering process $\phi + \phi\rightarrow \phi + \phi$ in a $\lambda…
We derive the tensor gravitational waveform generated by a binary of nonspinning compact objects (black holes or neutron stars) in a general class of scalar-tensor theories of gravity. The waveform is accurate to second post-Newtonian order…
We calculate the explicit equations of motion for non-spinning compact objects to 2.5 post-Newtonian order, or O(v/c)^5 beyond Newtonian gravity, in a general class of scalar-tensor theories of gravity. We use the formalism of the Direct…