Talks

12145 - 12156 of 19958 Results

Constructing theories from duality: my response to John Wheeler

October 17, 2013

PIRSA:13100072

General Relativity & Quantum Cosmology
Quasinormal modes of rapidly rotating black holes/ Stability of tidally perturbed neutron stars

Aaron Zimmerman The University of Texas at Austin

October 17, 2013

PIRSA:13100096

General Relativity & Quantum Cosmology
13/14 PSI - Statistical Mechanics - Lecture 8

Anton Burkov University of Waterloo

October 17, 2013

PIRSA:13100054
13/14 PSI - Quantum Field Theory I - Lecture 7

Freddy Cachazo Perimeter Institute for Theoretical Physics

October 16, 2013

PIRSA:13100029
Simulating Hamiltonian evolution with quantum computers

Richard Cleve Institute for Quantum Computing (IQC)

October 16, 2013

PIRSA:13100097

Quantum Physics
13/14 PSI - Statistical Mechanics - Lecture 7

Anton Burkov University of Waterloo

October 16, 2013

PIRSA:13100053
Topics in QFT on Flat and Curved Spacetimes - Lecture 8

Ugo Moschella University of Insubria

October 16, 2013

PIRSA:13100017
General Relativity for Cosmology - Lecture 8

Achim Kempf University of Waterloo

October 15, 2013

PIRSA:13100105
General Relativity for Cosmology - Lecture 7

Achim Kempf University of Waterloo

October 15, 2013

PIRSA:13100003
Can ‘sub-quantum’ theories based on a background field escape Bell’s no-go theorem ?

Louis Vervoort Université de Montréal

October 15, 2013

PIRSA:13100085

Quantum Physics
Geometry of quantum phases and emergent Newtonian dynamics

Anatoli Polkovnikov Boston University

October 15, 2013

PIRSA:13100083

Condensed Matter
13/14 PSI - Quantum Field Theory I - Lecture 6

Freddy Cachazo Perimeter Institute for Theoretical Physics

October 15, 2013

PIRSA:13100028

Constructing theories from duality: my response to John Wheeler

October 17, 2013

PIRSA:13100072

General Relativity & Quantum Cosmology

The late physicist John Wheeler, was renowned for his Socratic method of conducting physics discussions. "Why is general relativity the way it is? What makes it special?" were reportedly questions one should expect in his presence. There are different answers to these questions, each requiring a set of assumptions - which Wheeler would likely question again - and each bringing with it new insights into physics as a whole. This talk will put forward new principles for deriving general relativity. Perhaps more than is the case with other construction principles, the principles introduced are not limited to the derivation of general relativity, requiring only an specification of the theory's phase space in order to be applicable. To be less enigmatic, one defines observable equivalence between physical theories in the Dirac constraint setting, and then the principle merely searches theory space for two equivalent (or dual) fully constrained theories. We find it quite remarkable that such a complex theory as general relativity emerges, when no initial presupposition even on the existence of space-time is made. If there is time (and I will argue there is!) I will discuss another issue that also distinguishes the present set of assumptions: the possibility that they are in a concrete sense ``self-selected", which I like to think would be more satisfactory to Wheeler's line of questioning (or at least give him more to chew on).
Quasinormal modes of rapidly rotating black holes/ Stability of tidally perturbed neutron stars

Aaron Zimmerman The University of Texas at Austin

October 17, 2013

PIRSA:13100096

General Relativity & Quantum Cosmology

I will review recent work in two very different topics. First, I will discuss the quasinormal mode spectrum of nearly extremal Kerr black holes, where a bifurcation of the frequency spectrum is observed. In addition, collective oscillations of many modes is possible, resulting in a power-law rather than exponentially decaying ringdown. Next, I will discuss a recent proposal for how tidally induced, multimode coupling of normal modes in neutron stars can destabilize the stars. Such an instability could hamper gravitational wave detection of neutron star binaries by matched filtering. By accounting for higher-order multimode couplings, it can be shown that there is no such instability for neutron star binaries, although a milder instability may exist for binaries with less compact objects.
13/14 PSI - Statistical Mechanics - Lecture 8

Anton Burkov University of Waterloo

October 17, 2013

PIRSA:13100054
13/14 PSI - Quantum Field Theory I - Lecture 7

Freddy Cachazo Perimeter Institute for Theoretical Physics

October 16, 2013

PIRSA:13100029
Simulating Hamiltonian evolution with quantum computers

Richard Cleve Institute for Quantum Computing (IQC)

October 16, 2013

PIRSA:13100097

Quantum Physics

In 1982, Richard Feynman proposed the concept of a quantum computer as a means of simulating physical systems that evolve according to the Schrödinger equation. I will explain various quantum algorithms that have been proposed for this simulation problem, including my recent work (jointly with Dominic Berry and Rolando Somma) that significantly improves the running time as a function of the precision of the output data.
13/14 PSI - Statistical Mechanics - Lecture 7

Anton Burkov University of Waterloo

October 16, 2013

PIRSA:13100053
Topics in QFT on Flat and Curved Spacetimes - Lecture 8

Ugo Moschella University of Insubria

October 16, 2013

PIRSA:13100017
General Relativity for Cosmology - Lecture 8

Achim Kempf University of Waterloo

October 15, 2013

PIRSA:13100105
General Relativity for Cosmology - Lecture 7

Achim Kempf University of Waterloo

October 15, 2013

PIRSA:13100003
Can ‘sub-quantum’ theories based on a background field escape Bell’s no-go theorem ?

Louis Vervoort Université de Montréal

October 15, 2013

PIRSA:13100085

Quantum Physics

In systems described by Ising-like Hamiltonians, such as spin-lattices, the Bell Inequality can be strongly violated. Surprisingly, these systems are both local and non-superdeterministic. They are local, because 1) they include only local, near-neighbor interaction, 2) they satisfy, accordingly, the Clauser-Horne factorability condition, and 3) they can violate the Bell Inequality also in dynamic Bell experiments. Starting from this result we construct an elementary hidden-variable model, based on a generalized Ising Hamiltonian, describing the interaction of the Bell-particles with a stochastic ‘background’ medium. We suggest that such a model is a simple version of a variety of recently developed ‘sub-quantum’ theories, by authors as Nelson, Adler, De la Pena, Cetto, Groessing, Khrennikov, all based on a background field. We investigate how the model might be turned into a realistic theory. Finally, it appears that background-based models can be tested and discriminated from quantum mechanics by a straightforward extension of existing experiments.
Geometry of quantum phases and emergent Newtonian dynamics

Anatoli Polkovnikov Boston University

October 15, 2013

PIRSA:13100083

Condensed Matter

In the first part of this talk I will discuss how one can characterize geometry of quantum phases and phase transitions based on the Fubini-Study metric, which characterizes the distance between ground state wave-functions in the external parameter space. This metric is closely related to the Berry curvature. I will show that there are new geometric invariants based on the Euler characteristic. I will also show how one can directly measure this metric tensor in simple dynamical experiments. In the second part of the talk I will discuss emergent nature of macroscopic equations of motion (like Newton's equations) showing that they appear in the leading order of non-adiabatic expansion. I will show that the Berry curvature gives the Coriolis force and the Fubini-Study metric tensor is closely related to the inertia mass. Thus I will argue that any motion (not necessarily motion in space) is geometrical in nature.
13/14 PSI - Quantum Field Theory I - Lecture 6

Freddy Cachazo Perimeter Institute for Theoretical Physics

October 15, 2013

PIRSA:13100028

Title	Date	Collection	Type	Info
Constructing theories from duality: my response to John Wheeler	2013‑10‑17	Quantum Gravity	Scientific Series	View details
Quasinormal modes of rapidly rotating black holes/ Stability of tidally perturbed neutron stars	2013‑10‑17	Strong Gravity	Scientific Series	View details
13/14 PSI - Statistical Mechanics - Lecture 8	2013‑10‑17	13/14 PSI - Statistical Mechanics	Course	View details
13/14 PSI - Quantum Field Theory I - Lecture 7	2013‑10‑16	13/14 PSI - Quantum Field Theory I	Course	View details
Simulating Hamiltonian evolution with quantum computers	2013‑10‑16	Colloquium	Scientific Series	View details
13/14 PSI - Statistical Mechanics - Lecture 7	2013‑10‑16	13/14 PSI - Statistical Mechanics	Course	View details
Topics in QFT on Flat and Curved Spacetimes - Lecture 8	2013‑10‑16	Topics in QFT on Flat and Curved Spacetimes	Course	View details
General Relativity for Cosmology - Lecture 8	2013‑10‑15	General Relativity for Cosmology - 2013	Course	View details
General Relativity for Cosmology - Lecture 7	2013‑10‑15	General Relativity for Cosmology - 2013	Course	View details
Can ‘sub-quantum’ theories based on a background field escape Bell’s no-go theorem ?	2013‑10‑15	Quantum Foundations	Scientific Series	View details
Geometry of quantum phases and emergent Newtonian dynamics	2013‑10‑15	Quantum Matter	Scientific Series	View details
13/14 PSI - Quantum Field Theory I - Lecture 6	2013‑10‑15	13/14 PSI - Quantum Field Theory I	Course	View details

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Format results

Constructing theories from duality: my response to John Wheeler

Quasinormal modes of rapidly rotating black holes/ Stability of tidally perturbed neutron stars

13/14 PSI - Statistical Mechanics - Lecture 8

13/14 PSI - Quantum Field Theory I - Lecture 7

Simulating Hamiltonian evolution with quantum computers

13/14 PSI - Statistical Mechanics - Lecture 7

Topics in QFT on Flat and Curved Spacetimes - Lecture 8

General Relativity for Cosmology - Lecture 8

General Relativity for Cosmology - Lecture 7

Can ‘sub-quantum’ theories based on a background field escape Bell’s no-go theorem ?

Geometry of quantum phases and emergent Newtonian dynamics

13/14 PSI - Quantum Field Theory I - Lecture 6

Constructing theories from duality: my response to John Wheeler

Quasinormal modes of rapidly rotating black holes/ Stability of tidally perturbed neutron stars

13/14 PSI - Statistical Mechanics - Lecture 8

13/14 PSI - Quantum Field Theory I - Lecture 7

Simulating Hamiltonian evolution with quantum computers

13/14 PSI - Statistical Mechanics - Lecture 7

Topics in QFT on Flat and Curved Spacetimes - Lecture 8

General Relativity for Cosmology - Lecture 8

General Relativity for Cosmology - Lecture 7

Can ‘sub-quantum’ theories based on a background field escape Bell’s no-go theorem ?

Geometry of quantum phases and emergent Newtonian dynamics

13/14 PSI - Quantum Field Theory I - Lecture 6