Event Time: Thursday, March 21, 2019 | 4:00 pm - 5:00 pm
Event Location:
Hennings 201
Add to Calendar 2019-03-21T16:00:00 2019-03-21T17:00:00 Engineering Correlated Physics in Two-Dimensional Moire Superlattices Event Information: Van der Waals heterostructures of atomically thin crystals offer an exciting new platform to design novel electronic and optical properties. In this talk, I will describe a general approach to engineer correlated physics using moire superlattice in two dimensional heterostructures. One example is the tunable Mott insulator realized in the ABC trilayer graphene (TLG) and hexagonal boron nitride (hBN) heterostructure with a moiré superlattice, where the moiré leads to narrow electronic minibands and allows for the observation of gate-tunable Mott insulator states at 1/4 and 1/2 fillings. In addition, signatures of superconductivity are observed at low temperature near the 1/4-filling Mott insulator state in the TLG/hBN heterostructures. Another example is the WS2/WSe2 heterostructure, where the moire superlattice leads to flat exciton subbands and emerging excitonic transitions. Event Location: Hennings 201
Event Time: Thursday, March 28, 2019 | 4:00 pm - 5:00 pm
Event Location:
Hennings 201
Add to Calendar 2019-03-28T16:00:00 2019-03-28T17:00:00 Making cosmological measurements with standard rulers and standard shapes Event Information: Analyses of galaxy clustering in redshift surveys such as the Baryon Oscillation Spectroscopic Survey (BOSS), have provided robust cosmological measurements and are now considered as one of the pillars of modern observational cosmology. The key technique uses Baryon Acoustic Oscillations as a standard ruler with which to measure the expansion of the Universe: finding the BAO scale within the galaxy survey fixes the distance-redshift relation. Complementary measurements can be made on smaller scales using voids as standard shapes - on average voids have no preferred orientation with respect to us, and this can be used to make cosmological measurements. I will introduce both BAO and void-based methods, and present recent results using both, confirming and refining the standard LCDM cosmological model. Future surveys including the Dark Energy Spectroscopic Instrument (DESI), the Euclid satellite mission and the MaunaKea Spectroscopic Explorer (as well as the related CHIME project, based at UBC), will provide an order of magnitude more information than BOSS and I will introduce these surveys and discuss predictions for the expected measurements. Event Location: Hennings 201