Talks

9157 - 9168 of 18100 Results

Observables and Change in Totally Constrained Systems

Karim Thebault Ludwig-Maximilians-Universitiät München (LMU)

September 18, 2014

PIRSA:14090004

General Relativity & Quantum Cosmology
Evolution of quantum field, particle content, and classicality in the three stage universe

Suprit Singh IUCAA - The Inter-University Centre for Astronomy and Astrophysics

September 18, 2014

PIRSA:14090082

Astrophysics
14/15 PSI Quantum Theory-9

Agata Branczyk IBM (Canada)

September 18, 2014

PIRSA:14090052
14/15 PSI - Relativity- Lecture 9

Neil Turok University of Edinburgh

September 18, 2014

PIRSA:14090021
A magic bullet for numerous quantum-informational tasks

Mark Howard University of Waterloo

September 17, 2014

PIRSA:14090006
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
14/15 PSI Quantum Theory-8

Joseph Emerson Institute for Quantum Computing (IQC)

September 17, 2014

PIRSA:14090051
Irreversibility, Entropy Production, and and Self-organization far from Equilibrium

Jeremy England Massachusetts Institute of Technology (MIT)

September 17, 2014

PIRSA:14090073

Condensed Matter
14/15 PSI - Relativity- Lecture 8

Neil Turok University of Edinburgh

September 17, 2014

PIRSA:14090018
Self-assembling tensor networks and holography in disordered spin chains

Andrew Goldsborough RWTH Aachen University

September 16, 2014

PIRSA:14090029

Condensed Matter
Infinite Chiral Symmetry in Four Dimensions

Wolfger Peelaers University of Oxford

September 16, 2014

PIRSA:14090079
Scalar Simplified Models and Dark Matter at Colliders

Matthew Buckley Rutgers University

September 16, 2014

PIRSA:14090080

High Energy Physics

Observables and Change in Totally Constrained Systems

Karim Thebault Ludwig-Maximilians-Universitiät München (LMU)

September 18, 2014

PIRSA:14090004

General Relativity & Quantum Cosmology

We isolate an important physical distinction between gauge symmetries which exist at the level of histories and states, and those which exist at the level of histories and not states. This distinction is characterised explicitly using a generalized Hamilton-Jacobi formalism within which a non-standard prescription for the observables of classical totally constrained systems is developed. These ideas motivate a `relational quantization' procedure which is different from the standard `Dirac quanization'. In particular, relational quantization of totally constrained systems leads to a formalism with superpositions of energy eigenstates and an enlarged set of quantum observables. These `Kucha\v{r} observables' can change independently of each other, and thus are associated with measurable quantities in excess of the `perennials' of the standard Dirac approach.
Evolution of quantum field, particle content, and classicality in the three stage universe

Suprit Singh IUCAA - The Inter-University Centre for Astronomy and Astrophysics

September 18, 2014

PIRSA:14090082

Astrophysics

I will discuss the evolution of a quantum scalar field in a toy universe which has three stages of evolution, viz., (i) an early (inflationary) de Sitter phase (ii) radiation-dominated phase and (iii) late-time (cosmological constant dominated) de Sitter phase. Using the Schr\"odinger picture, the scalar field equations are solved separately for the three stages and matched at the transition points. The boundary conditions are chosen so that field modes in the early de Sitter phase evolve from the Bunch-Davies vacuum state. I shall look the (time-dependent) particle content of this quantum state for the entire evolution of the universe and describe the various features both numerically and analytically. I shall also describe the quantum to classical transition in terms of a classicality parameter which tracks the particle creation and its effect on phase space correlation of the quantum field.
14/15 PSI Quantum Theory-9

Agata Branczyk IBM (Canada)

September 18, 2014

PIRSA:14090052
14/15 PSI - Relativity- Lecture 9

Neil Turok University of Edinburgh

September 18, 2014

PIRSA:14090021
A magic bullet for numerous quantum-informational tasks

Mark Howard University of Waterloo

September 17, 2014

PIRSA:14090006

A class of d-level quantum states called "magic states", whose initial purpose was to enable universal fault-tolerant computation within error-correcting codes, has a surprisingly broad range of applications. We begin by describing their structure with respect to the Clifford hierarchy, and in terms of convex geometry before proceeding to their applications. They appear to have some relevance to the search for SIC-POVMs in certain prime dimensions. A version of the CHSH non-local game, using a d-ary alphabet and Pauli measurements, has an optimal quantum strategy using magic states. Finally, magic states exhibit nice symmetries (balanced, minimum uncertainty) with respect to Pauli measurements and consequently could find applications in areas like cryptography.
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.
14/15 PSI Quantum Theory-8

Joseph Emerson Institute for Quantum Computing (IQC)

September 17, 2014

PIRSA:14090051
Irreversibility, Entropy Production, and and Self-organization far from Equilibrium

Jeremy England Massachusetts Institute of Technology (MIT)

September 17, 2014

PIRSA:14090073

Condensed Matter

In the last few decades, substantial advances have been made in our ability to make general statements about the thermodynamics of systems driven far from thermal equilibrium. In this talk, I will give a brief overview of some the most basic results in this area and explain their connection to classic results in linear response theory. I will then describe how to formally construct the generalization of free energy for macrostates in a far-from-equilibrium system and discuss possible connections to self-organization phenomena in both biological and other contexts.
14/15 PSI - Relativity- Lecture 8

Neil Turok University of Edinburgh

September 17, 2014

PIRSA:14090018
Self-assembling tensor networks and holography in disordered spin chains

Andrew Goldsborough RWTH Aachen University

September 16, 2014

PIRSA:14090029

Condensed Matter

We show that the numerical strong disorder renormalization group algorithm (SDRG) of Hikihara et.\ al.\ [{Phys. Rev. B} {\bf 60}, 12116 (1999)] for the one-dimensional disordered Heisenberg model naturally describes a tree tensor network (TTN) with an irregular structure defined by the strength of the couplings. Employing the holographic interpretation of the TTN in Hilbert space, we compute expectation values, correlation functions and the entanglement entropy using the geometrical properties of the TTN. We find that the disorder averaged spin-spin correlation scales with the average path length through the tensor network while the entanglement entropy scales with the minimal surface connecting two regions. Furthermore, the entanglement entropy increases with both disorder and system size, resulting in an area-law violation. Our results demonstrate the usefulness of a self-assembling TTN approach to disordered systems and quantitatively validate the connection between holography and quantum many-body systems.
Infinite Chiral Symmetry in Four Dimensions

Wolfger Peelaers University of Oxford

September 16, 2014

PIRSA:14090079

We describe a new correspondence between four-dimensional conformal field theories with extended supersymmetry and two-dimensional chiral algebras. We explore the resulting chiral algebras in the context of theories of class S. The class S duality web implies nontrivial associativity properties for the corresponding chiral algebras, the structure of which can be summarized by a generalized topological quantum field theory.
Scalar Simplified Models and Dark Matter at Colliders

Matthew Buckley Rutgers University

September 16, 2014

PIRSA:14090080

High Energy Physics

Dark matter is clear evidence of the existence of new physics beyond the Standard Model, and there are compelling reasons to expect that this physics can be probed at the LHC. As we prepare for Run II, we must consider a wide range of possible phenomenology, leaving no stone unturned. In this talk, I present a set of scalar and pseudoscalar models which provide a useful framework to interpret dark matter results, and can motivate new searches in novel channels at the LHC.

Title	Date	Collection	Type	Info
Observables and Change in Totally Constrained Systems	2014‑09‑18	Quantum Gravity	Scientific Series	View details
Evolution of quantum field, particle content, and classicality in the three stage universe	2014‑09‑18	Cosmology and Gravitation	Scientific Series	View details
14/15 PSI Quantum Theory-9	2014‑09‑18	14/15 PSI - Quantum Theory	Course	View details
14/15 PSI - Relativity- Lecture 9	2014‑09‑18	14/15 PSI -Relativity	Course	View details
A magic bullet for numerous quantum-informational tasks	2014‑09‑17	Perimeter Institute Quantum Discussions	Scientific Series	View details
Boltzmann's Dog and Darwin's Finch: The statistical thermodynamics of self-replication and evolution	2014‑09‑17	Colloquium	Scientific Series	View details
14/15 PSI Quantum Theory-8	2014‑09‑17	14/15 PSI - Quantum Theory	Course	View details
Irreversibility, Entropy Production, and and Self-organization far from Equilibrium	2014‑09‑17	Quantum Matter	Scientific Series	View details
14/15 PSI - Relativity- Lecture 8	2014‑09‑17	14/15 PSI -Relativity	Course	View details
Self-assembling tensor networks and holography in disordered spin chains	2014‑09‑16	Quantum Matter	Scientific Series	View details
Infinite Chiral Symmetry in Four Dimensions	2014‑09‑16	Quantum Fields and Strings	Scientific Series	View details
Scalar Simplified Models and Dark Matter at Colliders	2014‑09‑16	Particle Physics	Scientific Series	View details

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Format results

Observables and Change in Totally Constrained Systems

Evolution of quantum field, particle content, and classicality in the three stage universe

14/15 PSI Quantum Theory-9

14/15 PSI - Relativity- Lecture 9

A magic bullet for numerous quantum-informational tasks

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

14/15 PSI Quantum Theory-8

Irreversibility, Entropy Production, and and Self-organization far from Equilibrium

14/15 PSI - Relativity- Lecture 8

Self-assembling tensor networks and holography in disordered spin chains

Infinite Chiral Symmetry in Four Dimensions

Scalar Simplified Models and Dark Matter at Colliders

Observables and Change in Totally Constrained Systems

Evolution of quantum field, particle content, and classicality in the three stage universe

14/15 PSI Quantum Theory-9

14/15 PSI - Relativity- Lecture 9

A magic bullet for numerous quantum-informational tasks

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

14/15 PSI Quantum Theory-8

Irreversibility, Entropy Production, and and Self-organization far from Equilibrium

14/15 PSI - Relativity- Lecture 8

Self-assembling tensor networks and holography in disordered spin chains

Infinite Chiral Symmetry in Four Dimensions

Scalar Simplified Models and Dark Matter at Colliders