Colloquium

Displaying 301 - 312 of 599

Colloquium - Testing gravity in the centre of the Galaxy

Michael Kramer Max Planck Institute for Astronomy
November 12, 2014
PIRSA:14110094
Strong Gravity
Quantum theory and spacetime: a different perspective
November 05, 2014
PIRSA:14110044
Quantum Foundations

Quantum Information
Experiments Big and Small

Savas Dimopoulos Perimeter Institute for Theoretical Physics

October 31, 2014
PIRSA:14100116
Quantum Fields and Strings at Finite Coupling

Pedro Vieira Perimeter Institute for Theoretical Physics

October 15, 2014
PIRSA:14100050
Defects: A new window into topological quantum matter

Maissam Barkeshli University of California, Santa Barbara

October 01, 2014
PIRSA:14100048
Boltzmann's Dog and Darwin's Finch: The statistical thermodynamics of self-replication and evolution

Jeremy England Massachusetts Institute of Technology (MIT)

September 17, 2014
PIRSA:14090003
Short-Range Entangled Phases and Topology

Anton Kapustin California Institute of Technology (Caltech) - Division of Physics Mathematics & Astronomy

September 10, 2014
PIRSA:14090002
On Quantum Tunnelling

Neil Turok University of Edinburgh
June 25, 2014
PIRSA:14060051
Cosmology
Analogue Models of Gravity: The ubiquitous space-time

Stefano Liberati SISSA International School for Advanced Studies
June 18, 2014
PIRSA:14060000
Quantum Gravity
Sequential growth dynamics and quantum random walks

David Meyer University of California, San Diego
June 11, 2014
PIRSA:14060042
Mathematical physics
Neutrino Wakes

Ue-Li Pen Canadian Institute for Theoretical Astrophysics (CITA)
June 06, 2014
PIRSA:14060041
Cosmology
How Much Information Can SUSY QM Conserve About SUSY QFT (Part-2)?

S. James Gates Jr. University of Maryland, College Park

June 04, 2014
PIRSA:14060005

Colloquium - Testing gravity in the centre of the Galaxy

Michael Kramer Max Planck Institute for Astronomy
November 12, 2014
PIRSA:14110094
Strong Gravity
The supermassive black hole in the centre of the Milky Way, Sgr A*, is an ideal target for testing the properties of black holes. A number of experiments are being prepared or conducted, such as the monitoring of stellar orbits, the search for radio pulsars or the recording of an image of the shadow of a event horizon. The talk puts these efforts in context with other tests of general relativity and its alternatives. I will also compare the approaches in the Galactic centre, while concentrating in particular on the prospects of using pulsars as probes, also in combination with event horizon imaging.
Quantum theory and spacetime: a different perspective
November 05, 2014
PIRSA:14110044
Quantum Foundations

Quantum Information
Quantum information theory has taught us that quantum theory is just one possible probabilistic theory among many others. In the talk, I will argue that this "bird's-eye" perspective does not only allow us to derive the quantum formalism from simple physical principles, but also reveals surprising connections between the structures of spacetime and probability which can be phrased as mathematical theorems about information-theoretic scenarios.
Experiments Big and Small

Savas Dimopoulos Perimeter Institute for Theoretical Physics

October 31, 2014
PIRSA:14100116

I will talk about the implications of the current LHC results and the Higgs discovery on the principle of Naturalness, that has been guiding particle physics for the last forty years. Then I will discuss the role that low energy experiments can play for the future of particle physics.
Quantum Fields and Strings at Finite Coupling

Pedro Vieira Perimeter Institute for Theoretical Physics

October 15, 2014
PIRSA:14100050

Gauge theories lie at the heart of our understanding of three of the four known forces in nature: the electromagnetic, weak and strong forces. Moreover, our best understood non-perturbative definition of a theory of quantum gravity is also given by a gauge theory. Yet, despite their absolutely central role in physics, gauge theories are still far from being tamed with our current theoretical tools. In this colloquium we shall explore the realm of quantum fields and strings at finite coupling and survey some of the exciting recent developments which are improving this state of affairs. The main character in our incursions will be a most symmetric gauge theory known as N=4 super Yang-Mills theory, often referred to as the harmonic oscillator of the twenty first century or, as it was most recently coined, as the Darth Vader theory.
Defects: A new window into topological quantum matter

Maissam Barkeshli University of California, Santa Barbara

October 01, 2014
PIRSA:14100048

Topologically ordered states, such as the fractional quantum Hall (FQH) states, are quantum states of matter with various exotic properties, including quasiparticles with fractional quantum numbers and fractional statistics, and robust topology-dependent ground state degeneracies. In this talk, I will describe a new aspect of topological states: their extrinsic defects. These include extrinsically imposed point-like or line-like defects that couple to the topological properties of the state in non-trivial ways. The extrinsic point defects localize topologically protected "parafermion" zero modes, which generalize the notion of Majorana fermion zero modes, and provide a new direction for realizing non-Abelian quantum statistics and topological quantum computation. The line defects allow direct quantum mechanical coupling between electrons and fractionalized anyons, leading to new ways to probe fractionalization. After describing the conceptual framework, I will focus on a specific set of experimental proposals, using conventional bilayer FQH states, to detect parafermion zero modes and to directly observe the long-predicted topological ground state degeneracy of FQH states. In the end I will comment on other ways in which extrinsic defects provide a new window into fractionalization.
Boltzmann's Dog and Darwin's Finch: The statistical thermodynamics of self-replication and evolution

Jeremy England Massachusetts Institute of Technology (MIT)

September 17, 2014
PIRSA:14090003

Living things operate according to well-known physical laws, yet it is challenging to discern specific, non-trivial consequences of these constraints for how an organism that is a product of evolution must behave. Part of the difficulty here is that life lives very far from thermal equilibrium, where many of our traditional theoretical tools fail us. However, recent developments in nonequilibrium statistical mechanics may help light a way forward. The goal of this talk will be to explain some of these developments, and show how they begin to offer a new perspective on the physics of self-replication, natural selection, and evolution.
Short-Range Entangled Phases and Topology

Anton Kapustin California Institute of Technology (Caltech) - Division of Physics Mathematics & Astronomy

September 10, 2014
PIRSA:14090002

Recently a new and rather unexpected connection between condensed matter physics and algebraic topology has been noted. Namely, it appears that phases of matter with an energy gap, no long-range entanglement, and fixed symmetry can be classified using cobordism theory. I will exhibit several examples of this connection and describe a possible explanation.
On Quantum Tunnelling

Neil Turok University of Edinburgh
June 25, 2014
PIRSA:14060051
Cosmology
One of the most basic but intriguing properties of quantum systems is their ability to `tunnel' between configurations which are classically disconnected. That is, processes which are classically impossible, are quantum allowed. In this talk I will outline a new, first-principles approach combining the semiclassical approximation with the concepts of post-selection and weak measurement. Its main virtue is to provide a real-time description within which sharp answers can be given to questions such as 'how long did the tunneling take' and 'where was the particle while it was tunneling?' Potential applications span a vast range, from laboratory tests to understanding black hole evaporation, the stability of the electroweak Higgs vacuum and the future of our universe, and the validity (or otherwise) of the "inflationary multiverse" scenario.
Analogue Models of Gravity: The ubiquitous space-time

Stefano Liberati SISSA International School for Advanced Studies
June 18, 2014
PIRSA:14060000
Quantum Gravity
Analogies have played a very important role in physics and mathematics, as they provide new ways of looking at problems that permit cross-fertilization of ideas among different branches of science. An analogue gravity model is a generic dynamical system (typically but not always based on condensed matter physics) where the propagation of excitations/perturbations can be described via hyperbolic equations of motion possibly characterized be one single metric element for all the perturbations. We shall review the historical development of this field, some of the systems proposed, and discuss several applications of this fruitful analogy mainly in the context of black hole physics and cosmology. While typical applications are in the realm of classical and quantum field theory on curved spacetime, I shall in the end also discuss recent developments which may provide insights about the possible nature of gravitational dynamics in emergent gravity scenarios.
Sequential growth dynamics and quantum random walks

David Meyer University of California, San Diego
June 11, 2014
PIRSA:14060042
Mathematical physics
Rideout and Sorkin proposed a classical dynamics for causal sets based upon a sequential growth model. Comparing it with models for sequential growth in other systems, and with the dual goals of generating manifold-like causal sets and finding a quantum dynamics for them, we propose some modifications to their model. The resulting, admittedly speculative, proposal is a type of quantum random walk. We explore its properties in some simple cases.
Neutrino Wakes

Ue-Li Pen Canadian Institute for Theoretical Astrophysics (CITA)
June 06, 2014
PIRSA:14060041
Cosmology
We identify a new non-linear neutrino wake effect, due to the streaming motions of neutrinos relative to dark matter, analogous to the Tseliakhovich-Hirata effect. We compute the effect in moving background perturbation theory, compare to direct n-body simulations, and forecast its observability in current and future surveys. Depending on neutrino mass, this effect could be observable in upcoming surveys through a cross correlation dipole in lensing and galaxies. Unlike previous cosmological neutrino effects, this depends primarily on neutrino mass, making it complementary to measurements that depend on neutrino density.
How Much Information Can SUSY QM Conserve About SUSY QFT (Part-2)?

S. James Gates Jr. University of Maryland, College Park

June 04, 2014
PIRSA:14060005

We provide additional evidence that supersymmetrical quantum mechanical systems can contain a remarkable amount of information about supersymmetrical field
theories in greater than one dimension.

Title	Speaker(s)	Date	Talk Type	Info
Colloquium - Testing gravity in the centre of the Galaxy	Michael Kramer	2014-11-12	Scientific Series	View details
Quantum theory and spacetime: a different perspective		2014-11-05	Scientific Series	View details
Experiments Big and Small	Savas Dimopoulos	2014-10-31	Scientific Series	View details
Quantum Fields and Strings at Finite Coupling	Pedro Vieira	2014-10-15	Scientific Series	View details
Defects: A new window into topological quantum matter	Maissam Barkeshli	2014-10-01	Scientific Series	View details
Boltzmann's Dog and Darwin's Finch: The statistical thermodynamics of self-replication and evolution	Jeremy England	2014-09-17	Scientific Series	View details
Short-Range Entangled Phases and Topology	Anton Kapustin	2014-09-10	Scientific Series	View details
On Quantum Tunnelling	Neil Turok	2014-06-25	Scientific Series	View details
Analogue Models of Gravity: The ubiquitous space-time	Stefano Liberati	2014-06-18	Scientific Series	View details
Sequential growth dynamics and quantum random walks	David Meyer	2014-06-11	Scientific Series	View details
Neutrino Wakes	Ue-Li Pen	2014-06-06	Scientific Series	View details
How Much Information Can SUSY QM Conserve About SUSY QFT (Part-2)?	S. James Gates Jr.	2014-06-04	Scientific Series	View details

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