Talks

10417 - 10428 of 16754 Results

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
12/13 PSI - Explorations on Quantum Information Lecture 5

David Cory Institute for Quantum Computing (IQC)

March 22, 2013

PIRSA:13030058

Quantum Information
Advanced General Relativity - Lecture 18

Rafael Sorkin Perimeter Institute for Theoretical Physics

March 21, 2013

PIRSA:13030022
Particle Acceleration by Magnetic Reconnection in Striped Pulsar Winds and Relativistic Jets

Lorenzo Sironi Columbia University

March 21, 2013

PIRSA:13030078

Strong Gravity
12/13 PSI - Explorations in Particle Theory Lecture 4

David Morrissey TRIUMF

March 21, 2013

PIRSA:13030068

Particle Physics
12/13 PSI - Explorations on Quantum Information Lecture 4

David Cory Institute for Quantum Computing (IQC)

March 21, 2013

PIRSA:13030057

Quantum Information
Frustrated Magnets and Quantum Spin Liquids

Steven White University of California, Irvine

March 20, 2013

PIRSA:13030097

Condensed Matter

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
12/13 PSI - Explorations on Quantum Information Lecture 5

David Cory Institute for Quantum Computing (IQC)

March 22, 2013

PIRSA:13030058

Quantum Information
Advanced General Relativity - Lecture 18

Rafael Sorkin Perimeter Institute for Theoretical Physics

March 21, 2013

PIRSA:13030022
Particle Acceleration by Magnetic Reconnection in Striped Pulsar Winds and Relativistic Jets

Lorenzo Sironi Columbia University

March 21, 2013

PIRSA:13030078

Strong Gravity

The relativistic wind of pulsars consists of toroidal stripes of opposite magnetic field polarity, separated by current sheets of hot plasma. By means of 2D and 3D particle-in-cell simulations, we investigate particle acceleration and magnetic field dissipation at the termination shock of a striped pulsar wind. At the shock, the flow compresses and the alternating fields annihilate by driven magnetic reconnection. Irrespective of the stripe wavelength "lambda" or the wind magnetization "sigma" (in the regime sigma>>1 of magnetically-dominated flows), shock-driven reconnection transfers all the magnetic energy of the alternating fields to the particles. As the value of lambda/(r_L*sigma) increases (here, r_L is the relativistic Larmor radius in the wind), the post-shock spectrum passes from a thermal Maxwellian to a flat power-law tail with slope around -1.5, populated by particles accelerated by the reconnection electric field. The limit lambda/(r_L*sigma)>>1 is realized in relativistic jets, where kink instabilities may seed the conditions for magnetic reconnection. Here, we find that the particle spectrum in the current sheet approaches a flat power-law tail with slope between -1.5 and -2, regardless of the conditions in the jet. The spectrum extends to higher energies for larger magnetizations or colder plasma temperatures, everything else being fixed. Our results place important constraints on the emission models of Pulsar Wind Nebulae and magnetically-dominated astrophysical jets.
12/13 PSI - Explorations in Particle Theory Lecture 4

David Morrissey TRIUMF

March 21, 2013

PIRSA:13030068

Particle Physics
12/13 PSI - Explorations on Quantum Information Lecture 4

David Cory Institute for Quantum Computing (IQC)

March 21, 2013

PIRSA:13030057

Quantum Information
Frustrated Magnets and Quantum Spin Liquids

Steven White University of California, Irvine

March 20, 2013

PIRSA:13030097

Condensed Matter

A quantum spin liquid is a solid whose atoms have magnetic moments but, because of quantum fluctuations, these moments fluctuate like a liquid even at zero temperature. Two dimensional spin liquids have been suggested as a way to produce high temperature superconductivity, and to build quantum computers. Just as helium is the only element which is a liquid at zero temperature, 2D spin liquids have been extremely difficult to find, despite decades of effort, raising the question, do realistic spin liquids even exist?
Recently, apparent spin liquids have been found experimentally, stimulating theoretical work to find simple model Hamiltonians of frustrated spin systems that have spin liquid ground states.

In this talk, I will give a broad overview of spin liquids and then focus on our simulations of the kagome Heisenberg model, a simple, realistic model of some of the recent experimental spin liquids, where we find a spin liquid ground state.

Title	Date	Collection	Type	Info
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
12/13 PSI - Explorations on Quantum Information Lecture 5	2013‑03‑22	12/13 PSI - Explorations on Quantum Information	Course	View details
Advanced General Relativity - Lecture 18	2013‑03‑21	Elements of General Relativity	Course	View details
Particle Acceleration by Magnetic Reconnection in Striped Pulsar Winds and Relativistic Jets	2013‑03‑21	Strong Gravity	Scientific Series	View details
12/13 PSI - Explorations in Particle Theory Lecture 4	2013‑03‑21	12/13 PSI - Explorations in Particle Theory	Course	View details
12/13 PSI - Explorations on Quantum Information Lecture 4	2013‑03‑21	12/13 PSI - Explorations on Quantum Information	Course	View details
Frustrated Magnets and Quantum Spin Liquids	2013‑03‑20	Colloquium	Scientific Series	View details

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