Talks

10309 - 10320 of 16652 Results

The Quantum Steering Ellipsoid

Sania Jevtic Imperial College London

March 26, 2013

PIRSA:13030112

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

March 26, 2013

PIRSA:13030111

Quantum Fields and Strings
Effective field theory of the unstable top (quark)

Alexander Penin University of Alberta

March 26, 2013

PIRSA:13030090

Particle Physics
Supersymmetric gauge theory and the Yangian - continued

Kevin Costello Perimeter Institute for Theoretical Physics

March 26, 2013

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

David Morrissey TRIUMF

March 26, 2013

PIRSA:13030073

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

David Cory Institute for Quantum Computing (IQC)

March 26, 2013

PIRSA:13030062

Quantum Information
Wick's theorem for Matrix Product states

Robert Huebener Freie Universität Berlin

March 25, 2013

PIRSA:13030117

Quantum Information
Dissecting holography with higher spins

Xi Yin Harvard University

March 25, 2013

PIRSA:13030098

Quantum Fields and Strings
Supersymmetric gauge theory and the Yangian

Kevin Costello Perimeter Institute for Theoretical Physics

March 25, 2013

PIRSA:13030114
12/13 PSI - Explorations in Particle Theory Lecture 6

David Morrissey TRIUMF

March 25, 2013

PIRSA:13030072

Particle Physics
12/13 PSI - Explorations on Quantum Information Lecture 6

David Cory Institute for Quantum Computing (IQC)

March 25, 2013

PIRSA:13030061

Quantum Information
12/13 PSI - Explorations in Particle Theory Lecture 5

David Morrissey TRIUMF

March 22, 2013

PIRSA:13030069

Particle Physics

The Quantum Steering Ellipsoid

Sania Jevtic Imperial College London

March 26, 2013

PIRSA:13030112

Quantum Foundations

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

Quantum Fields and Strings

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

Particle 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 Perimeter Institute for Theoretical Physics

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

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

David Cory Institute for Quantum Computing (IQC)

March 26, 2013

PIRSA:13030062

Quantum Information
Wick's theorem for Matrix Product states

Robert Huebener Freie Universität Berlin

March 25, 2013

PIRSA:13030117

Quantum Information

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
Dissecting holography with higher spins

Xi Yin Harvard University

March 25, 2013

PIRSA:13030098

Quantum Fields and Strings

The holographic correspondence is a powerful duality between a quantum theory of gravity and a quantum gauge theory in one lower space-time dimension. Higher spin gravity theories, i.e. gravity theories that also contain (gauge) fields of spins greater than 2, play a special role in holography. I will explain consistent interacting higher spin gravity theories in anti-de Sitter space, their duality with gauged conformal vector models, and their connection to string theory.
Supersymmetric gauge theory and the Yangian

Kevin Costello Perimeter Institute for Theoretical Physics

March 25, 2013

PIRSA:13030114

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 6

David Morrissey TRIUMF

March 25, 2013

PIRSA:13030072

Particle Physics
12/13 PSI - Explorations on Quantum Information Lecture 6

David Cory Institute for Quantum Computing (IQC)

March 25, 2013

PIRSA:13030061

Quantum Information
12/13 PSI - Explorations in Particle Theory Lecture 5

David Morrissey TRIUMF

March 22, 2013

PIRSA:13030069

Particle Physics

Title	Date	Collection	Type	Info
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
Dissecting holography with higher spins	2013‑03‑25	Colloquium	Scientific Series	View details
Supersymmetric gauge theory and the Yangian	2013‑03‑25	Colloquium	Scientific Series	View details
12/13 PSI - Explorations in Particle Theory Lecture 6	2013‑03‑25	12/13 PSI - Explorations in Particle Theory	Course	View details
12/13 PSI - Explorations on Quantum Information Lecture 6	2013‑03‑25	12/13 PSI - Explorations on Quantum Information	Course	View details
12/13 PSI - Explorations in Particle Theory Lecture 5	2013‑03‑22	12/13 PSI - Explorations in Particle Theory	Course	View details

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