Past Events

Dissertation Defense: "Rate and State Friction Laws for Interfacial Chemical Bondinduced Friction at the Nanoscale"
October 11, 2017  10:00 am  12:00 pm
David Rittenhouse Laboratory, 3W2
Kaiwen (Kevin) Tian (U of Penn)

HET & HEE Joint Seminar: "Digging Deeper for New Physics in the LHC Data"
October 10, 2017  1:30 pm
Center for Particle Cosmology
David Shih (Rutgers University)

PHYSICS & ASTRONOMY CAREER SEMINAR: 10 Essential Steps to Successful Job Hunting for Physics PhD Students
October 5, 2017  12:00 pm
David Rittenhouse Laboratory, 3W2
Dr. Joseph Barber, Senior Associate Director (Penn Career Services)
Whether you are applying for faculty positions or for jobs in the broad range of other industries/fields that value a STEM PhD, there is plenty you can and should be doing throughout your PhD to position yourself for success. Attend this session to get advice about what to do in your limited professional and career development time to understand yourself and your career goals, explore your career options, and to develop an effective job searching strategy.

Condensed Matter Seminar: "The Case for an Exciton Metal in Bilayer Graphene"
October 4, 2017  4:00 pm  5:00 pm
David Rittenhouse Laboratory, A4
Michael Zaletel (Princeton University)
Graphene based heterostructures have emerged as a pristine platform for exploring the interplay of symmetry, topology and nonAbelian excitations in the quantum Hall regime. I will begin with a theoretical review of the quantum Hall effect in bilayer graphene before discussing results in collaboration with the Young Lab at UCSB. Using insitu control of the density and electromagnetic fields, they find a rich phase diagram which features a plateau at halffilling of a Landau level with a gap several times larger than previously observed.

High Energy Theory Seminar: (TBA)
October 2, 2017  2:00 pm
David Rittenhouse Laboratory, 2N36
Mukund Rangamani (UC Davis)

Joint Mathematics & Physics Seminar: 6D SCFTs and Group Theory
September 28, 2017  4:30 pm
David Rittenhouse Laboratory, 4C2
Tom Rudelius (IAS)
Certain classes of superconformal field theories in six dimensions (6D SCFTs) are in onetoone correspondence with certain classes of group homomorphisms. In this talk, we will see that this correspondence allows us to classify homomorphisms that were previously unknown in the mathematics literature and understand aspects of 6D SCFTs that were previously unknown in the physics literature. We speculate on the implications for the future study of 6D SCFTs and these group homomorphisms.

Condensed Matter Seminar: "Jamming of noncircular and deformable particles"
September 27, 2017  4:00 pm  5:00 pm
David Rittenhouse Laboratory, A4
Mark Shattuck (City University of New York)
We study mechanically stable packings of deformable and rigid 2D circulopolygons using computer simulations. A 2D circulopolygon is a particle shape formed by the collection of all points equidistant from the edge of a polygon. It is a generalization of the 2D circulocylinder and a circle, which are the collections of all points equidistance from a line and a point, respectively. In our model, the circulopolygon can be deformable, where the only constraint on the particle is that shape factor, the ratio of the area of the polygon to the square of the perimeter, is fixed.

Astro Seminar: "Cosmology with Galaxy Clusters: from Weighing the Giants to LSST"
September 27, 2017  2:00 pm
Anja von der Linden (Stony Brook)
Surveys of galaxy clusters provide a sensitive probe of cosmology by measuring the evolution of the halo mass function. However, already current cluster surveys are systematically limited by uncertainties in the relation between cluster mass and observables (e.g. Xray luminosity, cluster richness, SZ decrement). Cluster weak lensing is the most promising observational method to calibrate the mass scaling to the needed precision but requires the control of systematic errors to a few percent each.

Physics Department Colloquium: Eye patches: The Evolution of Novel Soft Matter
September 13, 2017  4:00 pm  6:00 pm
David Rittenhouse Laboratory  A8
Alison Sweeney (U of Penn)
Life on Earth constitutes the most sophisticated iterations in the known universe of what physicists classify as soft matter. Research in my group focuses on learning the physical rules of soft matter selfassembly phenomena via the evolutionary processes by which they arose over Earth’s history. In this view of life as soft matter, evolution, with its own formal rules and algorithms, governs the appearance and diversification of novel forms of soft matter. The field of soft matter was until very recently restricted to analytical consideration of simpler systems like isotr

HET & HEE Joint Seminar: "Applications of the Average Null Energy Condition"
September 12, 2017  1:30 pm
Center for Particle Cosmology
Clay Cordova, (IAS Princeton)
Local energy conditions are the key hypothesis in many classical results in general relativity. In quantum theory, these local energy conditions are invalidated due to quantum fluctuations. Nevertheless a weaker condition, the socalled average null energy condition still holds in quantum field theory. I will explain how this condition constrains the data of conformal field theories such as operator product coefficients and scaling dimensions.