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 Events
University of Austin
Mon 27 Apr 2015, 2:00pm SPECIAL
CRG Geometry and Physics Seminar
ESB 2012 (Note that this is not the usual room)
Betti Geometric Langlands
ESB 2012 (Note that this is not the usual room)
Mon 27 Apr 2015, 2:00pm-3:00pm

Abstract

The Betti geometric Langlands program is a new physics-inspired variant of the [de Rham] geometric Langlands program, in which the geometry of algebraic curves is replaced by the topology of surfaces. It has close relations to representation theory of quantum groups, Hecke algebras and p-adic groups. I will describe some features of and progress on this program, following work with David Nadler as well as Adrien Brochier, David Jordan and Anatoly Preygel.
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Scuola Normale Superiore
Mon 27 Apr 2015, 3:30pm SPECIAL
CRG Geometry and Physics Seminar
ESB 2012 (Note that this is not the usual room)
Cohomological invariants of algebraic stacks (after Robert Pirisi)
ESB 2012 (Note that this is not the usual room)
Mon 27 Apr 2015, 3:30pm-4:30pm

Abstract

 Galois cohomological invariants for algebraic groups are an arithmetic analogue of characteristic classes in algebraic topology; Totaro and Guillot connected them to unramified étale cohomology and Rost’s higher Chow Groups.

In his PhD thesis, Roberto Pirisi generalizes the theory of Galois cohomological invariants to smooth Artin stacks of finite type over a field, and computes the cohomological invariants for stacks of hyperelliptic curves of even genus. Furthermore he defines Rost’s higher Chow groups for Artin stacks.
 
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PhD Candidate: Michael R Lindstrom
Mathematics, UBC
Thu 7 May 2015, 9:00am SPECIAL
One Time Event
Room 203, Graduate Student Centre, UBC
Exam: Investigation into the Feasibility and Operation of a Magnetized Target Fusion Reactor, and Qualitative Predictions of Magnetic Field Profile Perturbations Induced by Surface Roughness in Type II Superconductors: Insights from Mathematical Modelling
Room 203, Graduate Student Centre, UBC
Thu 7 May 2015, 9:00am-11:00am

Details

In this thesis we study two problems, one concerning fusion energy and another superconductivity.

Magnetized target fusion reactors are a modern idea to generate hydrogen fusion energy on earth. The design entails magnetically confining a plasma and crushing it in an imploding shell of molten metal. The design has many unresolved questions in its feasibility as a power source and its efficiency. We study the problem with two approaches. Firstly, we use a coordinate transformation and implement a novel flux-limited, split-step, finite volume scheme for nonlinear coupled conservation laws and do a parameter sensitivity analysis for the performance. Secondly, by a careful series of asymptotic arguments, we establish a leading order expression for the plasma compression. This expression is qualitatively consistent with numerical simulations, but it also gives new insights into the device operation. We then infer key design parameters for the success of magnetized target fusion.

The second problem involves computational modelling of superconductors. In type II superconductors where the coherence length ξ is small compared to the London penetration depth λ, the London equation predicts that magnetic fields decay exponentially in magnitude with the depth into the superconductor with length scale λ, provided the surface is flat. Various measurements of λ using low energy muon spin rotation on superconductors such as Yttrium-Barium-Copper-Oxide measure field profiles that differ from this prediction. There seems to be a dead layer, a distance δ over which the magnetic field magnitude does not decay. Speculation has been made that this may be due to surface roughness. Surface roughness has been studied for a simple sinusoidal model of surface roughness. We extend this work firstly by using Atomic Force Microscopy data of Yttrium-Barium-Copper-Oxide (a type II superconductor) crystals and predicting the field profiles the crystals could produce with the London model given their actual surface geometry; and secondly, we consider how roughness could affect experimental values for λ and δ. We find that dead layers are unlikely due to roughness alone, that the measurement of λ may be influenced by surface roughness, and that the field orientation may be perturbed, negligibly, within the superconductor.
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University of Utah
Wed 13 May 2015, 3:10pm
Diff. Geom, Math. Phys., PDE Seminar / Probability Seminar
MATH 203
MATH 203
Wed 13 May 2015, 3:10pm-4:00pm

Abstract

 
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UCLA
Thu 21 May 2015, 3:30pm
Number Theory Seminar
room MATH 126
TBA
room MATH 126
Thu 21 May 2015, 3:30pm-4:30pm

Abstract

 
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Mon 25 May 2015, 11:30am SPECIAL
One Time Event
MATH 126
Mathematics Grad Reception
MATH 126
Mon 25 May 2015, 11:30am-1:00pm

Details

The luncheon and awards presentation will be followed by the Niven Lecture at 1:15pm.
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Duke University
Mon 25 May 2015, 1:15pm SPECIAL
Department Colloquium
MATX 1100
Niven lecture: Surfing with wavelets
MATX 1100
Mon 25 May 2015, 1:15pm-2:15pm

Abstract

Wavelets provide a mathematical tool that emerged in the 1980s from a synthesis of ideas in mathematics, physics, computer science and engineering. They are now used in a wide range of mathematical applications, and provide a mathematical way to "zoom in" on details, without losing track of the large picture. The talk will describe some of the essential features of the approach, and illustrate with examples.

Note for Attendees

There will be the Grad Reception on Monday, May 25th at 11:30-1:00 (lunch and awards presentation).
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Fri 11 Sep 2015, 3:00pm
Department Colloquium
reserved
Fri 11 Sep 2015, 3:00pm-4:00pm

Abstract


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Yakov Sinai
Princeton University
Fri 23 Oct 2015, 3:00pm SPECIAL
Department Colloquium / PIMS Seminars and PDF Colloquiums
ESB2012
TBA-PIMS/UBC Distinguished Colloquium
ESB2012
Fri 23 Oct 2015, 3:00pm-4:00pm
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