相关论文: Finding Principal Null Direction for Numerical Rel…

Tensor and scalar unparticle couplings to matter have been shown to enhance gravitational interactions and provide corrections to the Schwarzschild metric and associated black hole structure. We derive an exact solution to the Einstein…

In this paper we revisit the analysis of the ringdown frequencies in the form of quasi-normal modes for Schwarzschild,Schwarzschild de-Sitter and Reissner-Nordstr\"om space-times. We plot these frequencies, using the third-order WKB…

Minimization methods that search along a curvilinear path composed of a non-ascent nega- tive curvature direction in addition to the direction of steepest descent, dating back to the late 1970s, have been an effective approach to finding a…

In this paper, we consider the three most general cases of progressive de Sitter spacetime. The charged and magnetic particles tunnel into the magnetically charged Reissner-Nordstr\"{o}m de Sitter black hole (the most general case of a…

The wide applications of higher dimensional gravity and gauge/gravity duality have fuelled the search for new stationary solutions of the Einstein equation (possibly coupled to matter). In this topical review, we explain the mathematical…

In the numerical investigation of the physical merger of two black holes, it is crucial to locate a black hole locally. This is usually done utilizing an apparent horizon. An alternative proposal is to identify a geometric horizon (GH),…

In this paper, we investigate some characteristics of phantom Reissner-Nordstr\"om-de Sitter (RN-dS) black holes. The peculiar feature of phantom field renders this kind of black holes quite different from their counterparts. We can only…

The study of the motion of photons around massive bodies is one of the most useful tools to know the geodesic structure associated with said gravitational source. In the present work, different possible paths projected in an invariant…

We extend a recently developed numerical code to obtain stationary, axisymmetric solutions that describe rotating black hole spacetimes in a wide class of modified theories of gravity. The code utilizes a relaxed Newton-Raphson method to…

Regular Schwarzschild Anti-de-Sitter (RSch-AdS) spacetime, which is a maximally symmetric and Lorentzian manifold of negative curvature, is a solution of Einstein's field equations with a negative cosmological constant and a matter source…

We present a novel family of slowly rotating black hole solutions in four, and higher dimensions, that extend the well known Lense-Thirring spacetime and solve the field equations to linear order in rotation parameter. As "exact metrics" in…

This work introduces the Nirenberg Neural Network: a numerical approach to the Nirenberg problem of prescribing Gaussian curvature on $S^2$ for metrics that are pointwise conformal to the round metric. Our mesh-free physics-informed neural…

In this Chapter we would like to review a "~phenomenological~" approach taking into account the most fundamental feature of string theory or, more in general, of quantum gravity, whatever its origin, which is the existence of a minimal…

Seminar held at JINR, Dubna, May 15, 2012. In General Relativity, spacetime singularities raise a number of problems, both mathematical and physical. One can identify a class of singularities - with smooth but degenerate metric - which,…

In this chapter we present a status report of black hole-like solutions in non-local theories of gravity in which the Lagrangians are at least quadratic in curvature and contain specific non-polynomial (i.e., non-local) operators. In the…

The characterization of a six- (or seven)-dimensional internal manifold with metric as having positive, zero or negative curvature is expected to be an important aspect of warped compactifications in supergravity. In this context, Douglas…

I have derived the Kretschmann scalar for a general black hole of mass m, angular momentum per unit mass a, and electric charge Q. The Kretschmann scalar gives the amount of curvature of spacetime, as a function of position near (and…

A new derivation of the five-dimensional Myers-Perry black-hole metric as a 2-soliton solution on a non-flat background is presented. It is intended to be an illustration of how the well-known Belinski-Zakharov method can be applied to find…

The Deser-Woodard gravity is a modified theory of gravity in which nonlocality plays a central role. In this context, nonlocality is a consequence of the inverse of the d'Alembertian operator $\square^{-1}$ in the effective action. Here,…

Numerical relativity has traditionally been pursued via finite differencing. Here we explore pseudospectral collocation (PSC) as an alternative to finite differencing, focusing particularly on the solution of the Hamiltonian constraint (an…