General Relativity & Quantum Cosmology

Displaying 1393 - 1404 of 1819

Canonical gravity using unconstrained null initial data

Michael Reisenberger Universidad de la Republica Uruguay
March 28, 2013

PIRSA:13030092
General Relativity & Quantum Cosmology
Particle Acceleration by Magnetic Reconnection in Striped Pulsar Winds and Relativistic Jets

Lorenzo Sironi Columbia University
March 21, 2013

PIRSA:13030078
General Relativity & Quantum Cosmology
A CDT Hamiltonian from Horava-Lifshitz gravity

Yuki Sato Nagoya University
March 14, 2013

PIRSA:13030091
General Relativity & Quantum Cosmology
The dynamics of asymptotically anti-de Sitter spacetimes

Claude Warnick
March 14, 2013

PIRSA:13030077
General Relativity & Quantum Cosmology
A Self-consistent Model of the Black Hole Evaporation

Yuki Yokokura RIKEN
March 07, 2013

PIRSA:13030093
General Relativity & Quantum Cosmology
Exploiting the Strong Gravitational Fields of Neutron Stars to Measure their Properties

Dimitrios Psaltis University of Arizona
February 28, 2013

PIRSA:13020126
General Relativity & Quantum Cosmology
Quantum Gravity as Random Geometry

Vincent Rivasseau University of Paris-Saclay
February 27, 2013

PIRSA:13020132
General Relativity & Quantum Cosmology
Gamma Rays at 130 GeV and How They Might Come from Dark Matter

Andrew Frey University of Winnipeg
February 21, 2013

PIRSA:13020139
Astrophysics

General Relativity & Quantum Cosmology
12/13 PSI - Quantum Gravity Review Lecture 14

Bianca Dittrich Perimeter Institute for Theoretical Physics
February 15, 2013

PIRSA:13020058
General Relativity & Quantum Cosmology
12/13 PSI - Gravitational Physics Review Lecture 15

Ruth Gregory King's College London
February 15, 2013

PIRSA:13020073
General Relativity & Quantum Cosmology
12/13 PSI - Quantum Gravity Review Lecture 13

Bianca Dittrich Perimeter Institute for Theoretical Physics
February 14, 2013

PIRSA:13020057
General Relativity & Quantum Cosmology
12/13 PSI - Gravitational Physics Review Lecture 14

Ruth Gregory King's College London
February 14, 2013

PIRSA:13020072
General Relativity & Quantum Cosmology

Canonical gravity using unconstrained null initial data

Michael Reisenberger Universidad de la Republica Uruguay
March 28, 2013

PIRSA:13030092
General Relativity & Quantum Cosmology
Particle Acceleration by Magnetic Reconnection in Striped Pulsar Winds and Relativistic Jets

Lorenzo Sironi Columbia University
March 21, 2013

PIRSA:13030078
General Relativity & Quantum Cosmology
The relativistic wind of pulsars consists of toroidal stripes of opposite magnetic field polarity, separated by current sheets of hot plasma. By means of 2D and 3D particle-in-cell simulations, we investigate particle acceleration and magnetic field dissipation at the termination shock of a striped pulsar wind. At the shock, the flow compresses and the alternating fields annihilate by driven magnetic reconnection. Irrespective of the stripe wavelength "lambda" or the wind magnetization "sigma" (in the regime sigma>>1 of magnetically-dominated flows), shock-driven reconnection transfers all the magnetic energy of the alternating fields to the particles. As the value of lambda/(r_L*sigma) increases (here, r_L is the relativistic Larmor radius in the wind), the post-shock spectrum passes from a thermal Maxwellian to a flat power-law tail with slope around -1.5, populated by particles accelerated by the reconnection electric field. The limit lambda/(r_L*sigma)>>1 is realized in relativistic jets, where kink instabilities may seed the conditions for magnetic reconnection. Here, we find that the particle spectrum in the current sheet approaches a flat power-law tail with slope between -1.5 and -2, regardless of the conditions in the jet. The spectrum extends to higher energies for larger magnetizations or colder plasma temperatures, everything else being fixed. Our results place important constraints on the emission models of Pulsar Wind Nebulae and magnetically-dominated astrophysical jets.
A CDT Hamiltonian from Horava-Lifshitz gravity

Yuki Sato Nagoya University
March 14, 2013

PIRSA:13030091
General Relativity & Quantum Cosmology
Causal Dynamical Triangulations” (CDT) is a lattice theory where aspects of quantum gravity can be studied. Two-dimensional CDT can be solved analytically and the continuum (quantum) Hamiltonian obtained.
In this talk I will show that this continuum Hamiltonian is the one obtained by quantizing two-dimensional projectable Horava-Lifshitz gravity.
The dynamics of asymptotically anti-de Sitter spacetimes

Claude Warnick
March 14, 2013

PIRSA:13030077
General Relativity & Quantum Cosmology
The majority of work on asymptotically anti-de Sitter spacetimes, much of it motivated by the AdS/CFT correspondence, assumes configurations which are either at or close to equilibrium. Recently it has been discovered that genuinely dynamical spacetimes with AdS asymptotics can exhibit some surprising behaviour. In particular, numerical studies suggest AdS is dynamically unstable. I will discuss recent analytical (in)stability results for asymptotically AdS spacetimes, in particular how stability can be affected by boundary conditions at the timelike conformal infinity.
A Self-consistent Model of the Black Hole Evaporation

Yuki Yokokura RIKEN
March 07, 2013

PIRSA:13030093
General Relativity & Quantum Cosmology
We construct a self-consistent model which describes a black hole from formation to evaporation including the back reaction from the Hawking radiation. In the case where a null shell collapses, at the beginning the evaporation occurs, but it stops eventually, and a horizon and singularity appear. On the other hand, in the generic collapse process of a continuously distributed null matter, the black hole evaporates completely without forming a macroscopically large horizon nor singularity. We also find a stationary solution in the heat bath, which can be regarded as a normal thermodynamic object. (hep-th: 1302.4733)
Exploiting the Strong Gravitational Fields of Neutron Stars to Measure their Properties

Dimitrios Psaltis University of Arizona
February 28, 2013

PIRSA:13020126
General Relativity & Quantum Cosmology
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.
Quantum Gravity as Random Geometry

Vincent Rivasseau University of Paris-Saclay
February 27, 2013

PIRSA:13020132
General Relativity & Quantum Cosmology
Matrix models, random maps and Liouville field theory are prime tools which connect random geometry and quantum gravity in two dimensions. The tensor track is a new program to extend this connection to higher dimensions through the corresponding notions of tensor models, colored triangulations and tensor group field theories.
Gamma Rays at 130 GeV and How They Might Come from Dark Matter

Andrew Frey University of Winnipeg
February 21, 2013

PIRSA:13020139
Astrophysics

General Relativity & Quantum Cosmology
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.
12/13 PSI - Quantum Gravity Review Lecture 14

Bianca Dittrich Perimeter Institute for Theoretical Physics
February 15, 2013

PIRSA:13020058
General Relativity & Quantum Cosmology
12/13 PSI - Gravitational Physics Review Lecture 15

Ruth Gregory King's College London
February 15, 2013

PIRSA:13020073
General Relativity & Quantum Cosmology
12/13 PSI - Quantum Gravity Review Lecture 13

Bianca Dittrich Perimeter Institute for Theoretical Physics
February 14, 2013

PIRSA:13020057
General Relativity & Quantum Cosmology
12/13 PSI - Gravitational Physics Review Lecture 14

Ruth Gregory King's College London
February 14, 2013

PIRSA:13020072
General Relativity & Quantum Cosmology

Title	Speaker(s)	Date	Talk Type	Info link
Canonical gravity using unconstrained null initial data	Michael Reisenberger	2013-03-28	Scientific Series	View details
Particle Acceleration by Magnetic Reconnection in Striped Pulsar Winds and Relativistic Jets	Lorenzo Sironi	2013-03-21	Scientific Series	View details
A CDT Hamiltonian from Horava-Lifshitz gravity	Yuki Sato	2013-03-14	Scientific Series	View details
The dynamics of asymptotically anti-de Sitter spacetimes	Claude Warnick	2013-03-14	Scientific Series	View details
A Self-consistent Model of the Black Hole Evaporation	Yuki Yokokura	2013-03-07	Scientific Series	View details
Exploiting the Strong Gravitational Fields of Neutron Stars to Measure their Properties	Dimitrios Psaltis	2013-02-28	Scientific Series	View details
Quantum Gravity as Random Geometry	Vincent Rivasseau	2013-02-27	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
12/13 PSI - Quantum Gravity Review Lecture 14	Bianca Dittrich	2013-02-15	Course	View details
12/13 PSI - Gravitational Physics Review Lecture 15	Ruth Gregory	2013-02-15	Course	View details
12/13 PSI - Quantum Gravity Review Lecture 13	Bianca Dittrich	2013-02-14	Course	View details
12/13 PSI - Gravitational Physics Review Lecture 14	Ruth Gregory	2013-02-14	Course	View details

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General Relativity & Quantum Cosmology

Format results

Canonical gravity using unconstrained null initial data

Particle Acceleration by Magnetic Reconnection in Striped Pulsar Winds and Relativistic Jets

A CDT Hamiltonian from Horava-Lifshitz gravity

The dynamics of asymptotically anti-de Sitter spacetimes

A Self-consistent Model of the Black Hole Evaporation

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

Quantum Gravity as Random Geometry

Gamma Rays at 130 GeV and How They Might Come from Dark Matter

12/13 PSI - Quantum Gravity Review Lecture 14

12/13 PSI - Gravitational Physics Review Lecture 15

12/13 PSI - Quantum Gravity Review Lecture 13

12/13 PSI - Gravitational Physics Review Lecture 14

Canonical gravity using unconstrained null initial data

Particle Acceleration by Magnetic Reconnection in Striped Pulsar Winds and Relativistic Jets

A CDT Hamiltonian from Horava-Lifshitz gravity

The dynamics of asymptotically anti-de Sitter spacetimes

A Self-consistent Model of the Black Hole Evaporation

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

Quantum Gravity as Random Geometry

Gamma Rays at 130 GeV and How They Might Come from Dark Matter

12/13 PSI - Quantum Gravity Review Lecture 14

12/13 PSI - Gravitational Physics Review Lecture 15

12/13 PSI - Quantum Gravity Review Lecture 13

12/13 PSI - Gravitational Physics Review Lecture 14