Talks

10513 - 10524 of 18100 Results

Quoins versus Coins

Terry Rudolph Imperial College London

March 27, 2013

PIRSA:13030000

Quantum Physics
12/13 PSI - Explorations in Particle Theory Lecture 8

David Morrissey TRIUMF

March 27, 2013

PIRSA:13030074

High Energy Physics
12/13 PSI - Explorations on Quantum Information Lecture 8

David Cory Institute for Quantum Computing (IQC)

March 27, 2013

PIRSA:13030063

Quantum Physics
Advanced General Relativity - Lecture 19

Rafael Sorkin Perimeter Institute for Theoretical Physics

March 26, 2013

PIRSA:13030027
Classifying fractionalization: symmetry classification of gapped Z2 spin liquids in two dimensions

Michael Hermele University of Colorado Boulder

March 26, 2013

PIRSA:13030116

Condensed Matter
The Quantum Steering Ellipsoid

Sania Jevtic Imperial College London

March 26, 2013

PIRSA:13030112

Quantum Physics
Comments on short strings and Wilson loops in AdS/CFT

March 26, 2013

PIRSA:13030111

High Energy Physics
Effective field theory of the unstable top (quark)

Alexander Penin University of Alberta

March 26, 2013

PIRSA:13030090

High Energy Physics
Supersymmetric gauge theory and the Yangian - continued

Kevin Costello

March 26, 2013

PIRSA:13030115
12/13 PSI - Explorations in Particle Theory Lecture 7

David Morrissey TRIUMF

March 26, 2013

PIRSA:13030073

High Energy Physics
12/13 PSI - Explorations on Quantum Information Lecture 7

David Cory Institute for Quantum Computing (IQC)

March 26, 2013

PIRSA:13030062

Quantum Physics
Wick's theorem for Matrix Product states

Robert Huebener Freie Universität Berlin

March 25, 2013

PIRSA:13030117

Quantum Physics

Quoins versus Coins

Terry Rudolph Imperial College London

March 27, 2013

PIRSA:13030000

Quantum Physics

Human monkeys are used to thinking about the problem of choosing from a set of objects according to some desired, biased, probability distribution. Just think about how you chose your partner(s). Even when it is easy for you to do such a sampling, it can be difficult to do a quantum sampling (Q-Sampling) of the same distribution. By Q-Sampling I mean the creation of a coherent superposition of states of such objects whose amplitudes are the (square roots of) of the specified distribution. In this talk I will discuss what we do know about this problem, why it is interesting, and will discuss how it can let us achieve tasks with quantum information that are provably impossible classically.
12/13 PSI - Explorations in Particle Theory Lecture 8

David Morrissey TRIUMF

March 27, 2013

PIRSA:13030074

High Energy Physics
12/13 PSI - Explorations on Quantum Information Lecture 8

David Cory Institute for Quantum Computing (IQC)

March 27, 2013

PIRSA:13030063

Quantum Physics
Advanced General Relativity - Lecture 19

Rafael Sorkin Perimeter Institute for Theoretical Physics

March 26, 2013

PIRSA:13030027
Classifying fractionalization: symmetry classification of gapped Z2 spin liquids in two dimensions

Michael Hermele University of Colorado Boulder

March 26, 2013

PIRSA:13030116

Condensed Matter

Quantum number fractionalization is a remarkable property of topologically ordered states of matter, such as fractional quantum Hall liquids, and quantum spin liquids. For a given type of topological order, there are generally many ways to fractionalize the quantum numbers of a given symmetry. What does it mean to have different types of fractionalization? Are different types of fractionalization a universal property that can be used to distinguish phases of matter? In this talk, I will answer these questions, focusing on a simple class of topologically ordered phases, namely two-dimensional gapped Z2 spin liquids, and I will present a symmetry classification of these phases. I will also discuss efforts in progress to find microscopic models realizing different symmetry classes.
The Quantum Steering Ellipsoid

Sania Jevtic Imperial College London

March 26, 2013

PIRSA:13030112

Quantum Physics

A quantum steering ellipsoid may be used to faithfully represent a density matrix ? describing two qubits A and B. The ellipsoid is the geometric set of states that Bob can steer Alice's qubit to when he implements all possible measurements on his qubit. We show how the correlations between qubits A and B manifest themselves in this paradigm, giving simple conditions for when the state is entangled, or has discord. We will also present novel features of the two qubit state that are revealed by the steering ellipsoid formalism, and show that a state corresponding to an ellipsoid with non-zero volume contains a new type of correlation.
Comments on short strings and Wilson loops in AdS/CFT

March 26, 2013

PIRSA:13030111

High Energy Physics

In the study of the string/gauge theory duality (AdS/CFT), an important role is played by the relation between local operators and Wilson loops. Perhaps the most well known example is the relation between twist two operators and the light-like cusp Wilson loop. On the string side, the twist two operator is represented by a "long" string (GKP). In this talk I use T-duality to argue that such relation is also natural for "short" strings. I discuss some examples and present a map between the shape of a short string crossing the Poincare horizon and the shape of a corresponding Wilson loop.
Based on arXiv:1212.4886 with Arkady Tseytlin (Imperial College).
Effective field theory of the unstable top (quark)

Alexander Penin University of Alberta

March 26, 2013

PIRSA:13030090

High Energy Physics

I introduce a new nonrelativistic effective field theory which systematically accounts for the finite lifetime effects in production of unstable particles.
The theory is applied to the threshold production of top quark-antiquark pairs.
Supersymmetric gauge theory and the Yangian - continued

Kevin Costello

March 26, 2013

PIRSA:13030115

I'll explain a new connection between supersymmetric gauge theories and the Yangian. The main result is that a twisted, deformed version of the pure N=1 supersymmetric gauge theory is controlled by the Yangian, in the same way that Chern-Simons theory is controlled by the quantum group. This result is used to give an exact calculation, in perturbation theory, of the expectation value of a certain net of n+m Wilson operators in the deformed N=1 gauge theory. This expectation value coincides with the partition function of a spin-chain integrable lattice model on an n-by-m doubly-periodic lattice.
12/13 PSI - Explorations in Particle Theory Lecture 7

David Morrissey TRIUMF

March 26, 2013

PIRSA:13030073

High Energy Physics
12/13 PSI - Explorations on Quantum Information Lecture 7

David Cory Institute for Quantum Computing (IQC)

March 26, 2013

PIRSA:13030062

Quantum Physics
Wick's theorem for Matrix Product states

Robert Huebener Freie Universität Berlin

March 25, 2013

PIRSA:13030117

Quantum Physics

Matrix product states and their continuous analogues are variational classes of states that capture quantum many-body systems or quantum fields with low entanglement; they are at the basis of the density-matrix renormalization group method and continuous variants thereof. In this talk we show that, generically, N-point functions of arbitrary operators in discrete and continuous translation invariant matrix product states are completely characterized by the corresponding two- and three-point functions. Aside from having important consequences for the structure of correlations in quantum states with low entanglement, this result provides a new way of reconstructing unknown states from correlation measurements e.g. for one-dimensional continuous systems of cold atoms. We argue that such a relation of correlation functions may help in devising perturbative approaches to interacting theories.

Joint work with Andrea Mari and Jens Eisert.
arXiv:1207.6537

Title	Date	Collection	Type	Info
Quoins versus Coins	2013‑03‑27	Colloquium	Scientific Series	View details
12/13 PSI - Explorations in Particle Theory Lecture 8	2013‑03‑27	12/13 PSI - Explorations in Particle Theory	Course	View details
12/13 PSI - Explorations on Quantum Information Lecture 8	2013‑03‑27	12/13 PSI - Explorations on Quantum Information	Course	View details
Advanced General Relativity - Lecture 19	2013‑03‑26	Elements of General Relativity	Course	View details
Classifying fractionalization: symmetry classification of gapped Z2 spin liquids in two dimensions	2013‑03‑26	Quantum Matter	Scientific Series	View details
The Quantum Steering Ellipsoid	2013‑03‑26	Quantum Foundations	Scientific Series	View details
Comments on short strings and Wilson loops in AdS/CFT	2013‑03‑26	Quantum Fields and Strings	Scientific Series	View details
Effective field theory of the unstable top (quark)	2013‑03‑26	Particle Physics	Scientific Series	View details
Supersymmetric gauge theory and the Yangian - continued	2013‑03‑26	Colloquium	Scientific Series	View details
12/13 PSI - Explorations in Particle Theory Lecture 7	2013‑03‑26	12/13 PSI - Explorations in Particle Theory	Course	View details
12/13 PSI - Explorations on Quantum Information Lecture 7	2013‑03‑26	12/13 PSI - Explorations on Quantum Information	Course	View details
Wick's theorem for Matrix Product states	2013‑03‑25	Perimeter Institute Quantum Discussions	Scientific Series	View details

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Format results

Quoins versus Coins

12/13 PSI - Explorations in Particle Theory Lecture 8

12/13 PSI - Explorations on Quantum Information Lecture 8

Advanced General Relativity - Lecture 19

Classifying fractionalization: symmetry classification of gapped Z2 spin liquids in two dimensions

The Quantum Steering Ellipsoid

Comments on short strings and Wilson loops in AdS/CFT

Effective field theory of the unstable top (quark)

Supersymmetric gauge theory and the Yangian - continued

12/13 PSI - Explorations in Particle Theory Lecture 7

12/13 PSI - Explorations on Quantum Information Lecture 7

Wick's theorem for Matrix Product states

Quoins versus Coins

12/13 PSI - Explorations in Particle Theory Lecture 8

12/13 PSI - Explorations on Quantum Information Lecture 8

Advanced General Relativity - Lecture 19

Classifying fractionalization: symmetry classification of gapped Z2 spin liquids in two dimensions

The Quantum Steering Ellipsoid

Comments on short strings and Wilson loops in AdS/CFT

Effective field theory of the unstable top (quark)

Supersymmetric gauge theory and the Yangian - continued

12/13 PSI - Explorations in Particle Theory Lecture 7

12/13 PSI - Explorations on Quantum Information Lecture 7

Wick's theorem for Matrix Product states