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Solutions of the dilaton field equations with applications to the soliton-black hole correspondence in generalised JT gravity
Soliton A black hole A two-dimensional gravity
2014/12/9
In this thesis, we explore connections between solitons, black holes, and harmonic maps in two-dimensional gravitation. Euclidean sine-Gordon theory, naturally admitting soliton solutions, and Schwarz...
Shower Center of Gravity and Hadronic Interaction Characteristics
Shower Center Gravity Hadronic Interaction Characteristics
2012/2/23
Equations for the center of gravity of the shower originated by high energy proton in the atmosphere are written and, within certain simplifications, solved for the case of logarithmically decreasing ...
We examine the existence of relativistic stars in f(T) modified gravity and explicitly construct several classes of static perfect fluid solutions. We derive the conservation equation from the complet...
Model-Independent Comparisons of Pulsar Timings to Scalar-Tensor Gravity
General Relativity Gravity Gravitation Scalar-Tensor Tensor-Scalar Neutron Stars Pulsars Binary Pulsars Double Pulsar
2011/10/14
Observations of pulsar timing provide strong constraints on scalar-tensor theories of gravity, but these constraints are traditionally quoted as limits on the microscopic parameters (like the Brans-Di...
Asymptotically safe gravity as a scalar-tensor theory and its cosmological implications
Asymptotically gravity scalar-tensor theory cosmological implications
2011/10/14
We study asymptotically safe gravity with Einstein-Hilbert truncation taking into account the renormalization group running of both gravitational and cosmological constants. We show the classical beha...
Energy Extraction and Particle Acceleration Around Rotating Black Hole in Horava-Lifshitz Gravity
Energy Extraction Particle Acceleration Around Rotating Horava-Lifshitz Gravity
2011/10/17
Penrose process on rotational energy extraction of the black hole (BH) in the original non-projectable Ho\v{r}ava-Lifshitz gravity is studied. The strong dependence of the extracted energy from the sp...
Abstract: We discuss the f(R) gravity model in which the origin of dark energy is identified as a modification of gravity. The Noether symmetry with gauge term is investigated for the f(R) cosmologica...
Homogeneous Solutions of Quadratic Gravity
Quadratic gravity eff ective gravity homogenous geometries
2011/10/17
It is believed that soon after the Planck time, Einstein's general relativity theory should be corrected to an effective quadratic theory. In this work we present the 3+1 decomposition for the zero vo...
Vainshtein mechanism in Gauss-Bonnet gravity and Galileon aether
Vainshtein mechanism Gauss-Bonnet gravity Galileon aether
2011/10/18
We derive field equations of Gauss-Bonnet gravity in 4 dimensions after dimensional reduction of the action and demonstrate that in this scenario Vainshtein mechanism operates in the flat spherically ...
Generalized from the so-called teleparallel gravity which is exactly equivalent to general relativity, the $f(T)$ gravity has been proposed as an alternative gravity model to account for the dark ener...
Violation of the first law of black hole thermodynamics in $f(T)$ gravity
Violation first law black hole thermodynamics $f(T)$ gravity
2011/10/18
We prove that the first law of black hole thermodynamics, $\delta Q=T\delta S$, is violated in $f(T)$ gravity. As a result, there always exists entropy production, which implies that the black hole th...
Stability analysis of a tidally excited internal gravity wave near the centre of a solar-type star
planetary systems stars: rotation binaries: close hydrodynamics waves instabilities
2011/9/15
We perform a stability analysis of a tidally excited nonlinear internal gravity wave near the centre of a solar-type star in two-dimensional cylindrical geometry. The motivation is to understand the t...
We show that in theories of generalised teleparallel gravity, whose Lagrangians are algebraic functions of the usual teleparallel Lagrangian, the action and the field equations are not invariant unde...
Inflationary Perturbations in Palatini Generalised Gravity
Inflationary Perturbations Palatini Generalised Gravity
2011/1/13
We examine the generation of primordial perturbations during an inflationary epoch in generalised theories of gravity when the equations of motion are derived using the Palatini variational principle...
Black holes in an ultraviolet complete quantum gravity
Black holes ultraviolet complete quantum gravity
2011/1/13
In this Letter we derive the gravity field equations by varying the action for an ultraviolet complete quantum gravity. Then we consider the case of a static source term and we determine an exact bla...