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Superselection Sectors in AdS/CFT - Joint Quantum Gravity and String Theory Seminar

Aron Wall University of Cambridge
October 10, 2013

PIRSA:13100066
General Relativity & Quantum Cosmology
Plasma without Plasma: Exploring Force-Free Magnetospheres

Sam Gralla University of Arizona
October 10, 2013

PIRSA:13100078
General Relativity & Quantum Cosmology
13/14 PSI - Statistical Mechanics - Lecture 4

Anton Burkov University of Waterloo

October 10, 2013

PIRSA:13100042
Einstein and the Fugu

Andrew Waldron University of California, Davis
October 10, 2013

PIRSA:13100101
Astrophysics
13/14 PSI - Quantum Field Theory I - Lecture 3

Freddy Cachazo Perimeter Institute for Theoretical Physics

October 09, 2013

PIRSA:13100022
From Supersolidity to Giant Plasticity: Defects in Quantum Crystals

John Beamish University of Alberta
October 09, 2013

PIRSA:13100065
Condensed Matter
13/14 PSI - Statistical Mechanics - Lecture 3

Anton Burkov University of Waterloo

October 09, 2013

PIRSA:13100041
Topics in QFT on Flat and Curved Spacetimes - Lecture 6

Ugo Moschella University of Insubria

October 09, 2013

PIRSA:13100016
General Relativity for Cosmology - Lecture 4

Achim Kempf University of Waterloo

October 08, 2013

PIRSA:13100100
General Relativity for Cosmology - Lecture 3

Achim Kempf University of Waterloo

October 08, 2013

PIRSA:13100002
13/14 PSI - Quantum Field Theory I - Lecture 2

Freddy Cachazo Perimeter Institute for Theoretical Physics

October 08, 2013

PIRSA:13100021
A Nearly Gaussian Hubble-patch in a non-Gaussian Universe

Marilena LoVerde University of Washington
October 08, 2013

PIRSA:13100076
Astrophysics

Superselection Sectors in AdS/CFT - Joint Quantum Gravity and String Theory Seminar

Aron Wall University of Cambridge
October 10, 2013

PIRSA:13100066
General Relativity & Quantum Cosmology
AdS/CFT is a duality relating the degrees of freedom in a D dimensional bulk gravity theory to a (D-1) dimensional theory living on the boundary. I will argue that in fact the boundary theory contains only a subset of the bulk observables. For each state of the boundary theory, there are multiple bulk states dual to it, which can be operationally distinguished by observers who fall across event horizons. Based on arXiv:1210.3590.
Plasma without Plasma: Exploring Force-Free Magnetospheres

Sam Gralla University of Arizona
October 10, 2013

PIRSA:13100078
General Relativity & Quantum Cosmology
Pulsars have enormous magnetic fields whose energy density dwarfs the rest mass density of their plasma magnetosphere. In this regime of a plasma, the particles drop out of the description, leaving a set of equations for the electromagnetic field alone. This non-linear, deterministic system is known as force-free electrodynamics, and turns out to have some beautiful and bizarre features. I will give a pedagogical introduction to these equations and their role in astrophysics and then discuss our recent contributions. We have taken a geometric viewpoint, using the null structure of spacetime to unify previous exact solutions and discover new ones. We have found non-stationary, non-axisymmetric solutions that describe the outer magnetosphere of pulsars, including those that are accelerated or torqued. We have derived the standard cartoon of the aligned pulsar magnetosphere from an explicit, minimal set of assumptions. Time permitting, I will also discuss some properties of black hole magnetospheres: Blandford-Znajek energy extraction, non-scattering force-free waves, and the no-ingrown-hair theorem.
13/14 PSI - Statistical Mechanics - Lecture 4

Anton Burkov University of Waterloo

October 10, 2013

PIRSA:13100042
Einstein and the Fugu

Andrew Waldron University of California, Davis
October 10, 2013

PIRSA:13100101
Astrophysics
13/14 PSI - Quantum Field Theory I - Lecture 3

Freddy Cachazo Perimeter Institute for Theoretical Physics

October 09, 2013

PIRSA:13100022
From Supersolidity to Giant Plasticity: Defects in Quantum Crystals

John Beamish University of Alberta
October 09, 2013

PIRSA:13100065
Condensed Matter
In 2004, Kim and Chan reported torsional oscillator experiments on 4He crystals which showed evidence of “non-classical rotational inertia”, the mass decoupling expected for a long-sought “supersolid” state. It soon became clear that this behavior is not a property of perfect crystals – defects are involved. In 2007, we made elastic measurements which showed, to our surprise, that the shear modulus of solid 4He increases dramatically below 0.2 K, with the same dependence on temperature, amplitude and 3He impurity concentration as the torsional oscillator anomaly. These shear modulus changes are due to dislocations and their interactions with impurities and vacancies. Our experiments raised an obvious question – could the torsional oscillator behavior be an artifact of the elastic changes, rather than evidence of supersolidity? During the past two years it has become clear that the answer is “yes” and interest has focused on the properties of dislocations in a quantum solid like 4He. By growing high quality single crystals in optical cells, we have now been able to explore the behavior of dislocations in 4He in unprecedented detail. In some crystals the dislocations reduce the shear modulus by more than 80%, an extraordinary effect we describe as “giant plasticity”. Solid helium has proved to be an ideal system in which to do materials science, as well as to address fundamental questions about quantum solids.
13/14 PSI - Statistical Mechanics - Lecture 3

Anton Burkov University of Waterloo

October 09, 2013

PIRSA:13100041
Topics in QFT on Flat and Curved Spacetimes - Lecture 6

Ugo Moschella University of Insubria

October 09, 2013

PIRSA:13100016
General Relativity for Cosmology - Lecture 4

Achim Kempf University of Waterloo

October 08, 2013

PIRSA:13100100
General Relativity for Cosmology - Lecture 3

Achim Kempf University of Waterloo

October 08, 2013

PIRSA:13100002
13/14 PSI - Quantum Field Theory I - Lecture 2

Freddy Cachazo Perimeter Institute for Theoretical Physics

October 08, 2013

PIRSA:13100021
A Nearly Gaussian Hubble-patch in a non-Gaussian Universe

Marilena LoVerde University of Washington
October 08, 2013

PIRSA:13100076
Astrophysics
Local-type primordial non-Gaussianity couples statistics of the curvature perturbation \zeta on vastly different physical scales. Because of this coupling, statistics (i.e. the polyspectra) of \zeta in our Hubble volume may not be representative of those in the larger universe -- that is, they may be biased. The bias depends on the local background value of \zeta, which includes contributions from all modes with wavelength k ~< H_0 and is therefore enhanced if the entire post-inflationary patch is large compared with our Hubble volume. I will discuss the bias to locally-measured statistics for general local-type non-Gaussianity. I will discuss three examples in detail: (i) the usual fNL, gNL model, (ii) a strongly non-Gaussian model with \zeta ~ \zeta_G^p, and (iii) two-field non-Gaussian initial conditions. In each scenario one may generate statistics in a Hubble-size patch that are weakly Gaussian and consistent with observations despite the fact that the statistics in the larger, post-inflationary patch look very different. Finally, I will present a worked example of how the variation in local statistics arises in the curvaton scenario.

Title	Date	Collection	Type	Info
Superselection Sectors in AdS/CFT - Joint Quantum Gravity and String Theory Seminar	2013‑10‑10	Quantum Gravity	Scientific Series	View details
Plasma without Plasma: Exploring Force-Free Magnetospheres	2013‑10‑10	Strong Gravity	Scientific Series	View details
13/14 PSI - Statistical Mechanics - Lecture 4	2013‑10‑10	13/14 PSI - Statistical Mechanics	Course	View details
Einstein and the Fugu	2013‑10‑10	Cosmology and Gravitation	Scientific Series	View details
13/14 PSI - Quantum Field Theory I - Lecture 3	2013‑10‑09	13/14 PSI - Quantum Field Theory I	Course	View details
From Supersolidity to Giant Plasticity: Defects in Quantum Crystals	2013‑10‑09	Colloquium	Scientific Series	View details
13/14 PSI - Statistical Mechanics - Lecture 3	2013‑10‑09	13/14 PSI - Statistical Mechanics	Course	View details
Topics in QFT on Flat and Curved Spacetimes - Lecture 6	2013‑10‑09	Topics in QFT on Flat and Curved Spacetimes	Course	View details
General Relativity for Cosmology - Lecture 4	2013‑10‑08	General Relativity for Cosmology - 2013	Course	View details
General Relativity for Cosmology - Lecture 3	2013‑10‑08	General Relativity for Cosmology - 2013	Course	View details
13/14 PSI - Quantum Field Theory I - Lecture 2	2013‑10‑08	13/14 PSI - Quantum Field Theory I	Course	View details
A Nearly Gaussian Hubble-patch in a non-Gaussian Universe	2013‑10‑08	Cosmology and Gravitation	Scientific Series	View details

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Format results

Superselection Sectors in AdS/CFT - Joint Quantum Gravity and String Theory Seminar

Plasma without Plasma: Exploring Force-Free Magnetospheres

13/14 PSI - Statistical Mechanics - Lecture 4

Einstein and the Fugu

13/14 PSI - Quantum Field Theory I - Lecture 3

From Supersolidity to Giant Plasticity: Defects in Quantum Crystals

13/14 PSI - Statistical Mechanics - Lecture 3

Topics in QFT on Flat and Curved Spacetimes - Lecture 6

General Relativity for Cosmology - Lecture 4

General Relativity for Cosmology - Lecture 3

13/14 PSI - Quantum Field Theory I - Lecture 2

A Nearly Gaussian Hubble-patch in a non-Gaussian Universe

Superselection Sectors in AdS/CFT - Joint Quantum Gravity and String Theory Seminar

Plasma without Plasma: Exploring Force-Free Magnetospheres

13/14 PSI - Statistical Mechanics - Lecture 4

Einstein and the Fugu

13/14 PSI - Quantum Field Theory I - Lecture 3

From Supersolidity to Giant Plasticity: Defects in Quantum Crystals

13/14 PSI - Statistical Mechanics - Lecture 3

Topics in QFT on Flat and Curved Spacetimes - Lecture 6

General Relativity for Cosmology - Lecture 4

General Relativity for Cosmology - Lecture 3

13/14 PSI - Quantum Field Theory I - Lecture 2

A Nearly Gaussian Hubble-patch in a non-Gaussian Universe