Talks

9421 - 9432 of 18375 Results

14/15 PSI - Relativity- Lecture 13

Neil Turok University of Edinburgh

September 24, 2014

PIRSA:14090062
Lifshitz Field Theories, Anomalies and Hydrodynamics

Shira Chapman University of Amsterdam

September 23, 2014

PIRSA:14090083
PHYS 781 - Lecture 1

Niayesh Afshordi University of Waterloo

September 23, 2014

PIRSA:14090084
14/15 PSI Quantum Theory-12

Joseph Emerson Institute for Quantum Computing (IQC)

September 23, 2014

PIRSA:14090057
14/15 PSI - Relativity- Lecture 12

Neil Turok University of Edinburgh

September 23, 2014

PIRSA:14090061
14/15 PSI Quantum Theory-11

Joseph Emerson Institute for Quantum Computing (IQC)

September 22, 2014

PIRSA:14090056
14/15 PSI - Relativity- Lecture 11

Neil Turok University of Edinburgh

September 22, 2014

PIRSA:14090025
Algebraic characterization of entanglement classes

Markus Grassl Max Planck Institute for the Science of Light

September 19, 2014

PIRSA:14090070

Quantum Physics
Conformal field theories at non-zero temperature: operator product expansions, Monte Carlo, and holography

September 19, 2014

PIRSA:14090072

High Energy Physics

Condensed Matter

General Relativity & Quantum Cosmology
14/15 PSI Quantum Theory-10

Joseph Emerson Institute for Quantum Computing (IQC)

September 19, 2014

PIRSA:14090053
14/15 PSI - Relativity- Lecture 10

Neil Turok University of Edinburgh

September 19, 2014

PIRSA:14090022
Observables and Change in Totally Constrained Systems

Karim Thebault Ludwig-Maximilians-Universitiät München (LMU)

September 18, 2014

PIRSA:14090004

General Relativity & Quantum Cosmology

14/15 PSI - Relativity- Lecture 13

Neil Turok University of Edinburgh

September 24, 2014

PIRSA:14090062
Lifshitz Field Theories, Anomalies and Hydrodynamics

Shira Chapman University of Amsterdam

September 23, 2014

PIRSA:14090083

I will review various aspects of field theories that posses a Lifshitz scaling symmetry. I will detail our study of the cohomological structure of anisotropic Weyl anomalies (the equivalent of trace anomalies in relativistic scale invariant field theories). I will also analyze the hydrodynamics of Lifshitz field theories and in particular of Lifshitz superfluids which may give insights into the physics of high temperature superconductors.
PHYS 781 - Lecture 1

Niayesh Afshordi University of Waterloo

September 23, 2014

PIRSA:14090084
14/15 PSI Quantum Theory-12

Joseph Emerson Institute for Quantum Computing (IQC)

September 23, 2014

PIRSA:14090057
14/15 PSI - Relativity- Lecture 12

Neil Turok University of Edinburgh

September 23, 2014

PIRSA:14090061
14/15 PSI Quantum Theory-11

Joseph Emerson Institute for Quantum Computing (IQC)

September 22, 2014

PIRSA:14090056
14/15 PSI - Relativity- Lecture 11

Neil Turok University of Edinburgh

September 22, 2014

PIRSA:14090025
Algebraic characterization of entanglement classes

Markus Grassl Max Planck Institute for the Science of Light

September 19, 2014

PIRSA:14090070

Quantum Physics

Entanglement is a key feature of composite quantum system which is directly related to the potential power of quantum computers. In most computational models, it is assumed that local operations are relatively easy to implement. Therefore, quantum states that are related by local operations form a single entanglement class. In the case of local unitary operations, a finite set of polynomial invariants provides a complete characterization of the entanglement classes. Unfortunately, one faces the problem of combinatorial explosion so that computing such a complete set of invariants becomes difficult already for quite small system. The two main problems in this context are to compute invariants and to decide completeness, i.e., whether a given set of invariants generates the full invariant ring. Important tools are both univariate and multivariate Hilbert series which are already difficult to compute. We will also address computational aspects of these problems and techniques for showing completeness of a set of invariants.
Conformal field theories at non-zero temperature: operator product expansions, Monte Carlo, and holography

September 19, 2014

PIRSA:14090072

High Energy Physics

Condensed Matter

General Relativity & Quantum Cosmology

We discuss properties of 2-point functions in CFTs in 2+1D at finite temperature. For concreteness, we focus on those involving conserved flavour currents, in particular on the associated conductivity. At frequencies much greater than the temperature, ω >> T, the ω dependence of the conductivity can be computed from the operator product expansion (OPE) between the currents and operators which acquire a non-zero expectation value at T > 0. Such results are found to be in excellent agreement with quantum Monte Carlo studies of the O(2) Wilson-Fisher CFT. Results for the conductivity and other observables are also obtained in vector 1/N expansions. We match these large ω results to the corresponding correlators of holographic representations of the CFT: the holographic approach then allows us to extrapolate to small ω/T. Other holographic studies implicitly only used the OPE between the currents and the energy-momentum tensor, and this yields the correct leading large ω behavior for a large class of CFTs. However, for the Wilson-Fisher CFT a relevant “thermal” operator must also be considered, and then consistency with the Monte Carlo results is obtained without a previously needed ad hoc rescaling of the T value [1]. We also use the OPE to prove sum rules obeyed by the conductivity. **In collaboration with A. Katz, S. Sachdev and E. Sørensen** [1] WWK, E. Sørensen, S. Sachdev, Nat. Phys. 10, 361 (2014)
14/15 PSI Quantum Theory-10

Joseph Emerson Institute for Quantum Computing (IQC)

September 19, 2014

PIRSA:14090053
14/15 PSI - Relativity- Lecture 10

Neil Turok University of Edinburgh

September 19, 2014

PIRSA:14090022
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.

Title	Date	Collection	Type	Info
14/15 PSI - Relativity- Lecture 13	2014‑09‑24	14/15 PSI -Relativity	Course	View details
Lifshitz Field Theories, Anomalies and Hydrodynamics	2014‑09‑23	Quantum Fields and Strings	Scientific Series	View details
PHYS 781 - Lecture 1	2014‑09‑23	PHYS 781 - Fundamentals of Astrophysics	Course	View details
14/15 PSI Quantum Theory-12	2014‑09‑23	14/15 PSI - Quantum Theory	Course	View details
14/15 PSI - Relativity- Lecture 12	2014‑09‑23	14/15 PSI -Relativity	Course	View details
14/15 PSI Quantum Theory-11	2014‑09‑22	14/15 PSI - Quantum Theory	Course	View details
14/15 PSI - Relativity- Lecture 11	2014‑09‑22	14/15 PSI -Relativity	Course	View details
Algebraic characterization of entanglement classes	2014‑09‑19	Perimeter Institute Quantum Discussions	Scientific Series	View details
Conformal field theories at non-zero temperature: operator product expansions, Monte Carlo, and holography	2014‑09‑19	Quantum Matter	Scientific Series	View details
14/15 PSI Quantum Theory-10	2014‑09‑19	14/15 PSI - Quantum Theory	Course	View details
14/15 PSI - Relativity- Lecture 10	2014‑09‑19	14/15 PSI -Relativity	Course	View details
Observables and Change in Totally Constrained Systems	2014‑09‑18	Quantum Gravity	Scientific Series	View details

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Format results

14/15 PSI - Relativity- Lecture 13

Lifshitz Field Theories, Anomalies and Hydrodynamics

PHYS 781 - Lecture 1

14/15 PSI Quantum Theory-12

14/15 PSI - Relativity- Lecture 12

14/15 PSI Quantum Theory-11

14/15 PSI - Relativity- Lecture 11

Algebraic characterization of entanglement classes

Conformal field theories at non-zero temperature: operator product expansions, Monte Carlo, and holography

14/15 PSI Quantum Theory-10

14/15 PSI - Relativity- Lecture 10

Observables and Change in Totally Constrained Systems

14/15 PSI - Relativity- Lecture 13

Lifshitz Field Theories, Anomalies and Hydrodynamics

PHYS 781 - Lecture 1

14/15 PSI Quantum Theory-12

14/15 PSI - Relativity- Lecture 12

14/15 PSI Quantum Theory-11

14/15 PSI - Relativity- Lecture 11

Algebraic characterization of entanglement classes

Conformal field theories at non-zero temperature: operator product expansions, Monte Carlo, and holography

14/15 PSI Quantum Theory-10

14/15 PSI - Relativity- Lecture 10

Observables and Change in Totally Constrained Systems