Physics Department Current Events
Wednesday, March 12, 2014
04:00 PM to 05:00 PM -- MR418N
Professor of Applied Physics and Applied Mathematics
"Probing van der Waals forces at the single-molecule level"
Single molecule junctions represent an attractive platform to understand and control functionality of materials and devices at the nanoscale. While their electronic transport properties have received tremendous attention thus far, measurements of mechanics are new and allow for a more complete understanding of the structure-function relationship at the atomic scale. Here we report simultaneous measurement of force and electrical conductance across single Au-Bipyridine-Au junctions using a conducting atomic force microscope (AFM). We show that van der Waals (vdW) interactions play a key role in the junction mechanics. Our measurements enable a quantitative characterization of vdW interactions at metal/organic interfaces in these single-molecule junctions1. 1Aradhya, S. V., Frei, M., Hybertsen, M. S. & Venkataraman, L., Nature Materials, 11, 872-876 (2012).
Friday, March 14, 2014
02:00 PM to 03:00 PM -- MR329
High Energy Seminar
Researcher, Department of Physics, Princeton University, Princeton, NJ
"Chern-Simons Vector Models and Bose-Fermi Dualities"
Abstract: I will talk about three-dimensional Chern-Simons matter theories with matter fields in the fundamental representation. These theories admit many simplifications in the large N limit, which allow us to perform many computations to all orders in the 't Hooft coupling. These computations imply that the Chern-Simons theory coupled to one scalar field is equivalent to the one with a single fermion. I will give a review of the computations supporting this conjecture, and discuss some of its simple generalizations.
Latha Venkataraman, Professor of Applied Physics and Applied Mathematics, Columbia University