This series consists of talks in areas where gravity is the main driver behind interesting or peculiar phenomena, from astrophysics to gravity in higher dimensions.
Millisecond
spin-period radio pulsars provide us with unique astronomical
"laboratories" for exploring fundamental physics in a variety of ways
-- from the physics of matter at super-nuclear density, to experimental tests
of gravity. They have also provided the only experimental evidence so far for
the existence of gravitational waves (GW). A set of millisecond pulsars
acting as precise astronomical clocks may also be used as a direct GW detector,
sensitive to the nanohertz-frequency GW expected to be emitted by supermassive
In this talk I will first review static black holes in
Kaluza-Klein theory. It is well-known that within this theory there exist black
strings which are non-uniform along the Kaluza-Klein circle. Using numerical
methods, I will explain how to construct (for the first time) non-uniform black
strings in D>10, where D is the total number of spacetime dimensions. The
stability of such black objects has not been discussed before, and in the last
part of the talk I will explain how one can study the stability of non-uniform
I will discuss recent work in simulating asymptotically
anti-de Sitter spacetimes, and its relation to heavy ion collider physics. For
this purpose, I intend to focus on a class of oblately deformed black hole
spacetime solutions. For each of these solutions, I will map the gravitational
metric in the spacetime bulk to a stress tensor one-point function of the
conformal field theory defined on the spacetime boundary. During the ring-down
process, wherein the deformed black hole settles down to the AdS analog of the
We study the gravitational collapse of the axion-dilaton
system suggested by type IIB string theory in dimensions ranging from four to
ten.
We extend previous analysis concerning the role played by
the global SL(2,
R) symmetry and also we explain ,why we do have three
different assumptions(cases). We evaluate the Choptuik exponents in the
elliptic case.
Eventually we try to explain some of the open
questions for two other assumptions and future directions.
After giving
an overview of the basic features of Horava gravity, I will focus on the latest developments and argue that, at least for the most general and complete version of the theory, the infrared phenomenology is by now relatively well understood and pathologies have been tamed. This implies that time has come for the theory to face a new series of intriguing challenges, related to quantization, ultraviolet phenomenology, black holes and singularities etc. I will present some ideas and first results in some of these directions.
I review the uses of effective field theory (EFT) techniques, originally developed in particle physics, to study gravitational dynamics. I will focus on the EFT approach to gravitational wave (GW) radiation, aka NRGR, and show how it has succeeded in producing the most accurate description of spinning binary systems to date, opening the door to a new era of precise astrophysical & cosmological measurements and tests of General Relativity via GW interferometry. I will also briefly discuss EFT applications for black hole dissipation/absorption, inflationary dynamics and high energy grav
Cosmological N-body simulations are now being performed using Newtonian gravity on scales larger than the Hubble radius. It is well known that a uniformly expanding, homogeneous ball of dust in Newtonian gravity satisfies the same equations as arise in relativistic FLRW cosmology, and it also is known that a correspondence between Newtonian and relativistic dust cosmologies continues to hold in linearized perturbation theory in the marginally bound/spatially flat case.
The observational search for non-Gaussian statistics in the initial conditions of the universe is a powerful,