Physics Department, Princeton University

Condensed Matter Seminar, Gregory A. Fiete, "Interacting topological insulators in oxides"
Topological phases of matter have received intense interest over the past few years due to the experimental discovery of time-reversal invariant topological insulators (TI) in two and three dimensions.  To date, the materials where TI have been reported are weakly interacting and most (if not all) have been previously predicted with simple band theory or density functional theory.  The fate of TI in the presence of interactions remains an open area of theoretical and experimental study.  In this talk, I will describe some of our theoretical efforts directed at the discovery and understanding of interacting topological phases in real materials.  Some of the most promising platforms for experimental realization of these phases are transition metal oxides and heterostructures derived from them.
PCTS Seminar Room  ·  1:15 p.m.– 2:30 p.m.

High Energy Theory Seminar - IAS - Rutger Boels, DESY - “New Applications of the Analytic S-matrix in String Theory”
The central drive of the analytic S-matrix program is to determine scattering amplitudes in any given theory from symmetries and analytic properties. This program led for instance to the birth of string theory with Veneziano's amplitude. Many recent developments in four dimensional field theory are closely related to this program. Here one of these, the notion of (linearized) on-shell superspace, will be extended to higher dimensions. Two main examples of the uses of these spaces will be presented in superstring theory in a flat background. First all three point amplitudes with one massive and two massless legs in the open superstring will be determined up to a normalization. Second a series of amplitudes in type IIB will be uncovered which in a precise sense violate R-symmetry maximally. These are a direct analog of four dimensional "MHV" amplitudes. Both examples display remarkable simplicity.
Bloomberg Lecture Hall  ·  2:30 p.m.– 3:30 p.m.

Gravity Group Astrophysics|Cosmology Lunch

Joseph Henry Room  ·  12:00 p.m.– 1:30 p.m.

High Energy Theory Seminar - Sumit Das, University of Kentucky - "Sp(N) Collective Fields and dS/CFT"

PCTS Seminar Room  ·  1:30 p.m.– 2:30 p.m.