There are no events at the Simons Center today. Here are the events for this week

Monday, May 20th, 2019

Weekly Physics Meeting: Indranil Halder

Time: 2:30 PM - 3:30 PM

Location: 313

Description:

__Title__: Matter Chern-Simons Theories in a Background Magnetic Field

__Abstract__: We study large N 2+1 dimensional fermions in the fundamental representation of an 𝑆𝑈(𝑁)𝑘 Chern Simons gauge group in the presence of a uniform background magnetic field for the U(1) global symmetry of this theory. The magnetic field modifies the Schwinger Dyson equation for the propagator in an interesting way; the product between the self energy and the Greens function is replaced by a Moyal star product. Employing a basis of functions previously used in the study of non-commutative solitons, we are able to exactly solve the Schwinger Dyson equation and so determine the fermion propagator. The propagator has a series of poles (and no other singularities) whose locations yield a spectrum of single particle energies at arbitrary t' Hooft coupling and chemical potential. The usual free fermion Landau levels spectrum is shifted and broadened out; we compute the shifts and widths of these levels at arbitrary t'Hooft coupling. As a check on our results we independently solve for the propagators of the conjecturally dual theory of Chern Simons gauged large N fundamental Wilson Fisher bosons also in a background magnetic field but this time only at zero chemical potential. The spectrum of single particle states of the bosonic theory precisely agrees with those of the fermionic theory under Bose-Fermi duality.

Tuesday, May 21st, 2019

SCGP Weekly Talk: Owen Gwilliam

Time: 1:00 PM - 2:00 PM

Location: 102

Description:

__Title__: Weaving higher algebra through strings and fields

__Abstract__: We will overview some ways that ideas from higher algebra (such as operads and categories) appear in field theory and string theory, emphasizing themes of this week's workshop.

Thursday, May 23rd, 2019

Hitchin Systems Program Seminar: Fernando Marchesano

Time: 1:00 PM - 2:30 PM

Location: SCGP 313

Description:

__Title__: T-branes and Hitchin systems

__Abstract__: T-branes are a specific class of Higgs bundles which are particularly relevant in string theory models of High Energy Physics. Their corresponding Hitchin system is defined over a complex surface, and they feature a Higgs field with a non-Abelian profile. We will review the T-branes that are nowadays most relevant in the context of string models, and the obstructions that one finds to their construction. We will do so for solutions to Hitchin systems with and without delta-like sources, and comment on the relation between both.

Friday, May 24th, 2019

Hitchin Program Journal Club - Misha Verbitsky

Time: 12:00 PM - 1:00 PM

Location: 313

Description:

__Title__: Holomorphic Lagrangian subvarieties, Lagrangian fibrations and special Kahler geometry

__Abstract__: Let $M$ be a holomorphic symplectic Kahler manifold equipped with a Lagrangian fibration with compact fibers. The base of this manifold is equipped with a special Kahler structure, that is, a Kahler structure $(I, g, \omega)$ and a symplectic flat torsion-free connection such that the metric $g$ is locally the Hessian of a function. We prove that any Lagrangian subvariety $Z\subset M$ which intersects smooth fibers of $\pi$ is a toric fibration over its image $\pi(Z)$ in $B$, and this image is also special Kahler. This answers a question of N. Hitchin related to Kapustin-Witten BBB/BAA duality. This is a joint work with Ljudmila Kamenova.