Strong Gravity

Displaying 241 - 252 of 298

Exploiting the Strong Gravitational Fields of Neutron Stars to Measure their Properties

Dimitrios Psaltis University of Arizona
February 28, 2013
PIRSA:13020126
Strong Gravity
Gamma Rays at 130 GeV and How They Might Come from Dark Matter

Andrew Frey University of Winnipeg
February 21, 2013
PIRSA:13020139
Cosmology

Strong Gravity
New transport properties of holographic superfluids

Daniel Fernandez University of Iceland
January 10, 2013
PIRSA:13010004
Strong Gravity
Approaches to modeling pulsar magnetospheres

Anatoly Spitkovsky Princeton University
December 06, 2012
PIRSA:12120001
Strong Gravity
Dynamical Capture Compact Binary Mergers

William East Perimeter Institute for Theoretical Physics
November 22, 2012
PIRSA:12110054
Strong Gravity
Detecting Gravitational Waves with Millisecond Pulsars

Paul Demorest National Radio Astronomy Observatory (NRAO)
November 15, 2012
PIRSA:12110044
Strong Gravity
Penrose inequalities and the stability of non-uniform black strings

Pau Figueras Queen Mary University of London

November 01, 2012
PIRSA:12110039
Towards an Asymptotically AdS Description of Heavy Ion Collisions

Hans Bantilan Princeton University
October 18, 2012
PIRSA:12100076
Quantum Fields and Strings
Testing Strong-Field General Relativity with Black Holes

Tim Johannsen

October 04, 2012
PIRSA:12100049
Critical Collapse in the Axion-Dilaton System in Diverse Dimensions

Ehsan Hatefi The Abdus Salam International Centre for Theoretical Physics (ICTP)
August 30, 2012
PIRSA:12080044
Quantum Fields and Strings
Where is the PdV term in the first law of black-hole thermodynamics?

Brian Dolan National University of Ireland

August 23, 2012
PIRSA:12080043
Coming of Age for Horava Gravity: from Renormalizability to Black Holes

Thomas Sotiriou University of Nottingham
March 22, 2012
PIRSA:12030085
Strong Gravity

Exploiting the Strong Gravitational Fields of Neutron Stars to Measure their Properties

Dimitrios Psaltis University of Arizona
February 28, 2013
PIRSA:13020126
Strong Gravity
Neutron stars possess the strongest gravitational fields among stellar objects in the Universe that are not surrounded by a horizon. This causes the emission from their surfaces to be strongly lensed and deformed. Two upcoming space X-ray missions, ESA's LOFT and NASA's NICER, aim to use observations of lightcurves from spinning neutron stars to map their gravitational fields as well as measure their masses and radii. In this talk, I will discuss some unexpected strong-field phenomena that affect gravitational lensing in the vicinity of neutron stars. I will then show how we can use these phenomena to measure strong-field frame dragging and break degeneracies in the measured neutron-star masses and radii.
Gamma Rays at 130 GeV and How They Might Come from Dark Matter

Andrew Frey University of Winnipeg
February 21, 2013
PIRSA:13020139
Cosmology

Strong Gravity
Gamma Rays at 130 GeV and How They Might Come from Dark Matter" I'll discuss the exciting (but somewhat controversial) new discovery of a sharp gamma ray feature at 130 GeV from near the galactic center and review some other evidence that might link it to annihilation of dark matter. I will then explain the challenges in understanding how dark matter might produce this signal and explain a model or two that overcome these difficulties.
New transport properties of holographic superfluids

Daniel Fernandez University of Iceland
January 10, 2013
PIRSA:13010004
Strong Gravity
In the context of holography applied to condensed matter theory, I will present an analysis of transport properties of p-wave superfluids by means of a gravity dual. Fluctuations modes in the SU(2) Einstein-Yang-Mills theory are considered, and phenomenological implications are derived. Due to the spatial anisotropy of the system, a non-universal shear viscosity is obtained, along with a new coefficient associated to normal stress differences. I will also discuss how the transport phenomena in this model is related to the thermoelectric, flexoelectric and piezoelectric effects (mixing of electric current, heat flux and mechanical stress), which have been observed in some superconductors and crystal liquids.
Approaches to modeling pulsar magnetospheres

Anatoly Spitkovsky Princeton University
December 06, 2012
PIRSA:12120001
Strong Gravity
Pulsars are rotating magnetized neutron stars that emit broadband pulses of radiation. Our ability to model magnetospheres of pulsars has been hampered by the difficulty of solving the self-consistent behavior of strongly magnetized relativistic plasmas. I will describe
recent progress in numerical modeling of magnetically-dominated plasmas and show applications to pulsar magnetospheres in increasing levels of realism, including ideal and resistive force-free,
relativistic MHD and kinetic models. The knowledge of the magnetospheric shape together with the new observations of gamma-ray emission from pulsars with Fermi telescope allow to directly constrain the location and physics of the acceleration regions in the magnetosphere and the origin of high energy emission. The pulsar magnetosphere is a prototype for other strongly magnetized
astrophysical objects, and I will discuss how the lessons from pulsar modeling can be useful in predicting EM counterparts to gravitational wave sources.
Dynamical Capture Compact Binary Mergers

William East Perimeter Institute for Theoretical Physics
November 22, 2012
PIRSA:12110054
Strong Gravity
Detecting Gravitational Waves with Millisecond Pulsars

Paul Demorest National Radio Astronomy Observatory (NRAO)
November 15, 2012
PIRSA:12110044
Strong Gravity
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 black hole binary systems or other more exotic sources. In this talk I will present the project status and recent GW upper limits from the NANOGrav project. I will also discuss expected near-future improvements in the measurement, including recent work aimed at better characterizing and mitigating the effect of multi-path propagation effects in the interstellar medium.
Penrose inequalities and the stability of non-uniform black strings

Pau Figueras Queen Mary University of London

November 01, 2012
PIRSA:12110039

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 black strings using Penrose inequalities. This will lead to a new conjecture for the phase diagram of static Kaluza-Klein black holes.
Towards an Asymptotically AdS Description of Heavy Ion Collisions

Hans Bantilan Princeton University
October 18, 2012
PIRSA:12100076
Quantum Fields and Strings
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 Schwarzschild solution, I will exhibit evidence that the dual CFT stress tensor on the boundary is that of an N=4 SYM fluid, even for black holes of significant deformation well outside the perturbative regime. We will conformally map the boundary fluid onto a real-world fluid in Minkowski space, and discover a temperature profile which can be thought of as approximating that of a head-on heavy ion collision at its moment of impact. I will close with a description of recent parallel explorations.
Testing Strong-Field General Relativity with Black Holes

Tim Johannsen

October 04, 2012
PIRSA:12100049
Critical Collapse in the Axion-Dilaton System in Diverse Dimensions

Ehsan Hatefi The Abdus Salam International Centre for Theoretical Physics (ICTP)
August 30, 2012
PIRSA:12080044
Quantum Fields and Strings
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.
Where is the PdV term in the first law of black-hole thermodynamics?

Brian Dolan National University of Ireland

August 23, 2012
PIRSA:12080043

TBA
Coming of Age for Horava Gravity: from Renormalizability to Black Holes

Thomas Sotiriou University of Nottingham
March 22, 2012
PIRSA:12030085
Strong Gravity
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.

Title	Speaker(s)	Date	Talk Type	Info
Exploiting the Strong Gravitational Fields of Neutron Stars to Measure their Properties	Dimitrios Psaltis	2013-02-28	Scientific Series	View details
Gamma Rays at 130 GeV and How They Might Come from Dark Matter	Andrew Frey	2013-02-21	Scientific Series	View details
New transport properties of holographic superfluids	Daniel Fernandez	2013-01-10	Scientific Series	View details
Approaches to modeling pulsar magnetospheres	Anatoly Spitkovsky	2012-12-06	Scientific Series	View details
Dynamical Capture Compact Binary Mergers	William East	2012-11-22	Scientific Series	View details
Detecting Gravitational Waves with Millisecond Pulsars	Paul Demorest	2012-11-15	Scientific Series	View details
Penrose inequalities and the stability of non-uniform black strings	Pau Figueras	2012-11-01	Scientific Series	View details
Towards an Asymptotically AdS Description of Heavy Ion Collisions	Hans Bantilan	2012-10-18	Scientific Series	View details
Testing Strong-Field General Relativity with Black Holes	Tim Johannsen	2012-10-04	Scientific Series	View details
Critical Collapse in the Axion-Dilaton System in Diverse Dimensions	Ehsan Hatefi	2012-08-30	Scientific Series	View details
Where is the PdV term in the first law of black-hole thermodynamics?	Brian Dolan	2012-08-23	Scientific Series	View details
Coming of Age for Horava Gravity: from Renormalizability to Black Holes	Thomas Sotiriou	2012-03-22	Scientific Series	View details

Strong Gravity

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