Related papers: Approximately stealth black hole in higher-order s…
We present a class of new nonsingular black holes in higher dimensional theories of gravity. Assuming a specific form of the stress energy tensor exact analytic solutions of the field equation are generated in general theory of relativity…
We construct higher-derivative gravity theories in three dimensions that admit holographic $c$-theorems and exhibit a unique maximally symmetric vacuum, at arbitrary order $n$ in the curvature. We show that these theories exhibit special…
Massive scalar charges are ubiquitous in extensions to General Relativity and the Standard Model in particle physics. We describe spectral methods which can accurately construct the spacetime of rotating black holes with dimensionless spin…
The investigation of gravity in higher-dimensional spacetime has transitioned from a mathematical curiosity to a fundamental framework in theoretical physics, catalyzed by the dimensional requirements of String theory and M-theory. In this…
We formulate the effective field theory (EFT) of vector-tensor gravity for perturbations around an arbitrary background with a ${\it timelike}$ vector profile, which can be applied to study black hole perturbations. The vector profile…
We consider the spike mass density profile in a dark halo by self-consistently solving the relativistic Bondi accretion of dark matter onto a non-spining black hole of mass $M$. We assume that the dominant component of the dark matter in…
We investigate the classical stability of the higher-dimensional Schwarzschild black holes against linear perturbations, in the framework of a gauge-invariant formalism for gravitational perturbations of maximally symmetric black holes,…
This work addresses spherically symmetric, static black holes in higher-derivative stringy gravity. We focus on the curvature-squared correction to the Einstein-Hilbert action, present in both heterotic and bosonic string theory. The string…
In this work, we investigate massive charged scalar perturbations in the background of three-dimensional dilaton black holes with a cosmological constant. We demonstrate that the wave equations governing the dynamics of these perturbations…
We present explicit black holes endowed with primary scalar hair within the shift-symmetric subclass of Beyond Horndeski theories. These solutions depend, in addition to the conventional mass parameter, on a second free parameter encoding…
General relativity admits a plethora of exact compact object solutions. The augmentation of Einstein's action with non-minimal coupling terms leads to modified theories with rich structure, which, in turn, provide non-trivial solutions with…
We study cosmic evolution based on the fixed points in the dynamical analysis of the Degenerate Higher-Order Scalar-Tensor (DHOST) theories. We consider the DHOST theory in which the propagation speed of gravitational waves is equal to the…
A spherically symmetric black hole solution defined by the gravitational mass is explored in higher-order curvature gravity associated with a scalar field. It is demonstrated that the singularities of the curvature invariants will be far…
In the present paper we study the scalar sector of the quasinormal modes of charged general relativistic, static and spherically symmetric black holes coupled to nonlinear electrodynamics and embedded in a class of scalar-tensor theories.…
The presented thesis is devoted to the study of instabilities of compact objects within the Einstein-Gauss-Bonnet theory. This theory includes higher-order corrections in curvature, which are inspired by the low energy limit of string…
Lovelock theory of gravity provides a tractable model to investigate the effects of higher-curvature terms in the context of AdS/CFT. Yielding second order, ghost-free field equations, this theory represents a minimal setup in which…
In this work we have developed a new stochastic model for the fluctuations in lightcurves of accreting black holes. The model is based on a linear combination of stochastic processes and is also the solution to the linear diffusion equation…
The sheer range of scales in the Universe makes it impossible to model all at once. It is necessary, therefore, when conducting numerical experiments, that we employ sub-resolution prescriptions that can represent the scales we are unable…
The discovery of cosmic acceleration has presented a unique challenge for cosmologists. As observational cosmology forges ahead, theorists have struggled to make sense of a standard model that requires extreme fine tuning. This challenge is…
We investigate how the ghost condensate reacts to black holes immersed in it. A ghost condensate defines a hypersurface-orthogonal congruence of timelike curves, each of which has the tangent vector u^\mu=-g^{\mu\nu}\partial_\nu\phi. It is…