Colloquium

607 talks

S001

Collection TypeSeries

SubjectPhysics

Source RepositoryPIRSA

Displaying 313 - 324 of 607

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
Astrophysics
Analogue Models of Gravity: The ubiquitous space-time

Stefano Liberati SISSA International School for Advanced Studies
June 18, 2014

PIRSA:14060000
General Relativity & Quantum Cosmology
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
Astrophysics
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
Equality

Tobias Fritz Universität Innsbruck

May 21, 2014

PIRSA:14050063
John Paul Robinson: Art, Science and Myth

May 02, 2014

PIRSA:14050062
Quantum thermalization and many-body Anderson localization

David Huse Princeton University
April 30, 2014

PIRSA:14040066
Quantum Physics
Conformal Standard Model

Krzysztof Meissner University of Warsaw

April 23, 2014

PIRSA:14040061

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
Astrophysics
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
General Relativity & Quantum Cosmology
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
Astrophysics
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.
Equality

Tobias Fritz Universität Innsbruck

May 21, 2014

PIRSA:14050063

Equality of two mathematical objects is a seemingly simple and well-understood concept. In this talk, I will do three things to explain why this is a misconception: I will survey different notions of equality, explain how revising the notion of equality has led to an emerging alternative foundation of mathematics called "homotopy type theory", and try to convince you that thinking about equality is relevant to your research in quantum field theory, quantum gravity or quantum foundations.
John Paul Robinson: Art, Science and Myth

May 02, 2014

PIRSA:14050062

Canadian glass artist and Renaissance man, John Paul Robinson, explores the mythic potential of science. Explaining that, “This is the idea that scientific discovery is changing our mythology by changing our understanding of the world and our place in it.” Backed with a firm understanding of the science he references, his sculptures poetically interpret such theoretical phenomena as wave particles, string mathematics and black holes. Most people, especially scientists see mythology and science as mutually exclusive and many believe that a scientific understanding of the world will eventually eliminate the need for myth. This idea is based on a misunderstanding as to what myth really is and it’s relationship to science. Myth is not superstition, fairy tail or lies nor is it truth, history or fact. Myth is Art. Myth is a picture, a story, a map; we use to navigate the world. Not the external material world but the world we all create and hold in our minds. In every human mind is a mythic picture of the world that provides the stage for all we experience. This picture not only helps us navigate our world but also performs the critical function of informing our sense of place and belonging within that world. Science cannot replace myth but it can inform it for mythology deals not with the mysteries generated by our ignorance of how the world works but by our understanding of how the world works. The mathematics of string theory is a powerful tool to describe the world but even physicists have to close their eyes and picture in their minds the world their equations are describing. The equation is pure logic and reason, but the picture of tiny strings playing the music that creates the universe is pure mythology. Award-winning glass artist and instructor John Paul Robinson was educated at the Georgian College of Arts and Technology in Barrie, Ontario, and the Ontario College of Art, where he subsequently taught for a number of years. His work has been exhibited in solo shows throughout Canada and the United States, in cities such as Montreal, Toronto and Chicago. Robinson’s works are held in the collections of The Museum of Civilization in Ottawa, Ontario, the Museum of American Glass in Millville, New Jersey and the Musée des Beaux-arts de Montréal, Québec. He has also created the Amber Archive, an annual participatory art project to communicate our existence and creative endeavours (by artists, designers and scientists) to beings millions of years in the future.
Quantum thermalization and many-body Anderson localization

David Huse Princeton University
April 30, 2014

PIRSA:14040066
Quantum Physics
Progress in physics and quantum information science motivates much recent study of the behavior of strongly-interacting many-body quantum systems fully isolated from their environment, and thus undergoing unitary time evolution. What does it mean for such a system to go to thermal equilibrium? I will explain the Eigenstate Thermalization Hypothesis (ETH), which posits that each individual exact eigenstate of the system's Hamiltonian is at thermal equilibrium, and which appears to be true for most (but not all) quantum many-body systems. Prominent among the systems that do not obey this hypothesis are quantum systems that are many-body Anderson localized and thus do not constitute a reservoir that can thermalize itself. When the ETH is true, one can do standard statistical mechanics using the `single-eigenstate ensembles', which are the limit of the microcanonical ensemble where the `energy window' contains only a single many-body quantum state. These eigenstate ensembles are more powerful than the traditional statistical mechanical ensembles, in that they can also "see" the quantum phase transition in to the localized phase, as well as a rich new world of phases and phase transitions within the localized phase.
Conformal Standard Model

Krzysztof Meissner University of Warsaw

April 23, 2014

PIRSA:14040061

I will describe a proposal of an enlargement of the Standard Model based on a softly broken conformal symmetry. It contains the usual particles of the SM with right-chiral neutrinos and predicts two new particles: a scalar mixing with the usual Higgs and a naturally weakly coupled axion. I will argue that the Planck scale should be treated as a real physical scale and discuss the hierarchy problem and renormalization from this point of view. I will show that the model does not need any intermediate scales and can be viable up to the Planck scale (in distiction to the Standard Model). I will present experimental predictions of the model.

Title	Speaker(s)	Date	Talk Type	Info
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
Equality	Tobias Fritz	2014-05-21	Scientific Series	View details
John Paul Robinson: Art, Science and Myth		2014-05-02	Scientific Series	View details
Quantum thermalization and many-body Anderson localization	David Huse	2014-04-30	Scientific Series	View details
Conformal Standard Model	Krzysztof Meissner	2014-04-23	Scientific Series	View details

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Format results

Defects: A new window into topological quantum matter

Boltzmann's Dog and Darwin's Finch: The statistical thermodynamics of self-replication and evolution

Short-Range Entangled Phases and Topology

On Quantum Tunnelling

Analogue Models of Gravity: The ubiquitous space-time

Sequential growth dynamics and quantum random walks

Neutrino Wakes

How Much Information Can SUSY QM Conserve About SUSY QFT (Part-2)?

Equality

John Paul Robinson: Art, Science and Myth

Quantum thermalization and many-body Anderson localization

Conformal Standard Model

Defects: A new window into topological quantum matter

Boltzmann's Dog and Darwin's Finch: The statistical thermodynamics of self-replication and evolution

Short-Range Entangled Phases and Topology

On Quantum Tunnelling

Analogue Models of Gravity: The ubiquitous space-time

Sequential growth dynamics and quantum random walks

Neutrino Wakes

How Much Information Can SUSY QM Conserve About SUSY QFT (Part-2)?

Equality

John Paul Robinson: Art, Science and Myth

Quantum thermalization and many-body Anderson localization

Conformal Standard Model