Talks

10501 - 10512 of 16447 Results

Astrophysical shear-driven turbulence

Jeremy Goodman
Princeton University

October 17, 2012

PIRSA:12100043
Quantum Field Theory - Lecture 7B

Konstantin Zarembo
Nordic Institute for Theoretical Physics

October 17, 2012

PIRSA:12100068

Quantum Fields and Strings
Condensed Matter - Lecture 7

Assa Auerbach
Technion – Israel Institute of Technology

October 17, 2012

PIRSA:12100030

Condensed Matter
Quantum Field Theory - Lecture 7A

Konstantin Zarembo
Nordic Institute for Theoretical Physics

October 17, 2012

PIRSA:12100012

Quantum Fields and Strings
Condensed Matter Seminar

Assa Auerbach
Technion – Israel Institute of Technology

October 16, 2012

PIRSA:12100078

Condensed Matter
Constraining RG flow in three-dimensional field theory

Benjamin Safdi
Massachusetts Institute of Technology (MIT)

October 16, 2012

PIRSA:12100054

Quantum Fields and Strings
Now what?: Higgs physics after discovery

Nathaniel Craig
University of California, Santa Barbara

October 16, 2012

PIRSA:12100060

Particle Physics
Maximum entropy, the universal dark matter density profile... and its destruction

Andrew Pontzen
University of Oxford

October 16, 2012

PIRSA:12100003

Cosmology
Quantum Field Theory - Lecture 6B

Konstantin Zarembo
Nordic Institute for Theoretical Physics

October 16, 2012

PIRSA:12100067

Quantum Fields and Strings
Condensed Matter - Lecture 6

Assa Auerbach
Technion – Israel Institute of Technology

October 16, 2012

PIRSA:12100029

Condensed Matter
Quantum Field Theory - Lecture 6A

Konstantin Zarembo
Nordic Institute for Theoretical Physics

October 16, 2012

PIRSA:12100011

Quantum Fields and Strings
The effect of initial correlations on the evolution of quantum states

Mark Byrd
Southern Illinois University

October 15, 2012

PIRSA:12100045

Quantum Information

Astrophysical shear-driven turbulence

Jeremy Goodman
Princeton University

October 17, 2012

PIRSA:12100043

Astronomical hydrodynamics is usually almost ideal in the sense that the Reynolds number (Re) is enormous and any effective viscosity must be due to shocks or turbulence. Astronomical magnetohydrodynamics (MHD) is often also nearly ideal, so that magnetic fields and plasma are well coupled. In particular, dissipation of orbital energy in accretion disks around black holes is readily explained by MHD turbulence. On the other hand, the planet-bearing disks around protostars are magnetically far from ideal because of very low fractional ionization. MHD turbulence is at best marginal in these disks, yet accretion is observed. The Reynolds numbers based on orbital-velocity gradients are enormous, so by analogy with high-Re terrestrial flows, one might expect hydrodynamic (i.e., unmagnetized) turbulence. Direct numerical simulations indicate that such turbulence is somehow suppressed by keplerian rotation, though the mechanism is
unclear and the simulations are limited in Re. Recently, a few groups have studied the question via Taylor-Couette experiments at somewhat higher Re, obtaining conflicting results. Complicating and enriching this debate is the recent discovery that turbulence tends to have a finite lifetime in shear flows that admit a formally linearly stable laminar solution: this includes flow in smooth pipes and probably also unmagnetized keplerian disks. Some suggestions will be offered as to how these open questions might be resolved.
Quantum Field Theory - Lecture 7B

Konstantin Zarembo
Nordic Institute for Theoretical Physics

October 17, 2012

PIRSA:12100068

Quantum Fields and Strings
Condensed Matter - Lecture 7

Assa Auerbach
Technion – Israel Institute of Technology

October 17, 2012

PIRSA:12100030

Condensed Matter
Quantum Field Theory - Lecture 7A

Konstantin Zarembo
Nordic Institute for Theoretical Physics

October 17, 2012

PIRSA:12100012

Quantum Fields and Strings
Condensed Matter Seminar

Assa Auerbach
Technion – Israel Institute of Technology

October 16, 2012

PIRSA:12100078

Condensed Matter
Constraining RG flow in three-dimensional field theory

Benjamin Safdi
Massachusetts Institute of Technology (MIT)

October 16, 2012

PIRSA:12100054

Quantum Fields and Strings

The entanglement entropy S(R) across a circle of radius R has been invoked recently in deriving general constraints on renormalization group flow in three-dimensional field theory. At conformal fixed points, the negative of the finite part of the entanglement entropy, which is called F, is equal to the free energy on the round three-sphere. The F-theorem states that F decreases under RG flow. Along the RG flow it has recently been shown that the renormalized entanglement entropy {\cal F}(R) = -S(R) + R S'(R), which is equal to F at the fixed points, is a monotonically decreasing function. I will review various three-dimensional field theories where we can calculate F on the three-sphere and compute its change under RG flow, including free field theories, perturbative fixed points, large N field theories with double trace deformations, gauge theories with large numbers of flavors, and supersymmetric theories with at least {\cal N} = 2 supersymmetry. I will also present calculations of the renormalized entanglement entropy along the RG flow in free massive field theory and in holographic examples.
Now what?: Higgs physics after discovery

Nathaniel Craig
University of California, Santa Barbara

October 16, 2012

PIRSA:12100060

Particle Physics

With the discovery of a new Higgs-like particle at the LHC, there is an unprecedented opportunity to use the Higgs as a probe for physics beyond the Standard Model. I will discuss a variety of recent ideas to look for new physics via the Higgs, including measurements of Higgs couplings and associated indirect observables; searches for Higgs production in association with new physics; and strategies for probing extended electroweak symmetry breaking sectors.
Maximum entropy, the universal dark matter density profile... and its destruction

Andrew Pontzen
University of Oxford

October 16, 2012

PIRSA:12100003

Cosmology

I review some recent developments in attempting to reconcile the observed galaxy population with numerical models of structure formation in the 'LCDM' concordance cosmology. Focussing on behaviour of dwarf galaxies, I describe the infamous 'cusp-core' dichotomy -- a long-standing challenge to the LCDM picture on small scales -- and use toy models to show how it is resolved in recent numerical simulations (Pontzen & Governato 2012). I then discuss the current observational status of this picture (Teyssier, Pontzen & Read 2012; Penarrubia et al 2012).

In the second half of the talk, I apply the analytic techniques developed for probing the effect of gas on dark matter dynamics to the question of how, in the absence of baryons, a universal "NFW" dark matter halo profile emerges (independent of scale or details of the initial conditions).

Thus the generation of NFW halos on the one hand and the destruction of their central cusps on the other can be ascribed to surprisingly similar physical arguments.
Quantum Field Theory - Lecture 6B

Konstantin Zarembo
Nordic Institute for Theoretical Physics

October 16, 2012

PIRSA:12100067

Quantum Fields and Strings
Condensed Matter - Lecture 6

Assa Auerbach
Technion – Israel Institute of Technology

October 16, 2012

PIRSA:12100029

Condensed Matter
Quantum Field Theory - Lecture 6A

Konstantin Zarembo
Nordic Institute for Theoretical Physics

October 16, 2012

PIRSA:12100011

Quantum Fields and Strings
The effect of initial correlations on the evolution of quantum states

Mark Byrd
Southern Illinois University

October 15, 2012

PIRSA:12100045

Quantum Information

Until fairly recently, it was generally assumed that the initial state of a quantum system prepared for information processing was in a product state with its environment. If this is the case,
the evolution is described by a completely positive map. However, if the system and environment are initially correlated, or entangled, such that the so-called quantum discord is non-zero, then the
evolution is described by a map which is not completely positive. Maps that are not completely positive are not as well understood and the implications of having such a map are not completely known. I will discuss a few examples and a theorem (or two) which may help us understand the implications of having maps which are not completely positive.

Title	Date	Collection	Type	Info
Astrophysical shear-driven turbulence	2012‑10‑17	Colloquium	Scientific Series	View details
Quantum Field Theory - Lecture 7B	2012‑10‑17	12/13 PSI - Quantum Field Theory 1	Course	View details
Condensed Matter - Lecture 7	2012‑10‑17	12/13 PSI - Condensed Matter	Course	View details
Quantum Field Theory - Lecture 7A	2012‑10‑17	12/13 PSI - Quantum Field Theory 1	Course	View details
Condensed Matter Seminar	2012‑10‑16		Other	View details
Constraining RG flow in three-dimensional field theory	2012‑10‑16	Quantum Fields and Strings	Scientific Series	View details
Now what?: Higgs physics after discovery	2012‑10‑16	Particle Physics	Scientific Series	View details
Maximum entropy, the universal dark matter density profile... and its destruction	2012‑10‑16	Cosmology and Gravitation	Scientific Series	View details
Quantum Field Theory - Lecture 6B	2012‑10‑16	12/13 PSI - Quantum Field Theory 1	Course	View details
Condensed Matter - Lecture 6	2012‑10‑16	12/13 PSI - Condensed Matter	Course	View details
Quantum Field Theory - Lecture 6A	2012‑10‑16	12/13 PSI - Quantum Field Theory 1	Course	View details
The effect of initial correlations on the evolution of quantum states	2012‑10‑15	Perimeter Institute Quantum Discussions	Scientific Series	View details

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