Past Events

  • Condensed Matter Seminar: "Revisiting and Repurposing the Double Helix"

    David Rittenhouse Laboratory, A6

    Taekjip Ha, Johns Hopkins University

    DNA is an iconic molecule that forms a double helical structure, providing the basis for genetic inheritance, and its physical properties have been studied for decades. In this talk, I will present evidence that sequence and methylation dependent physical properties of DNA such as flexibility and self-association may be important for biological functions [1, 2]. In addition, I will present a new application of DNA where mechanical modulations of cell behavior can be studied at the single molecule level using rupturable DNA tethers [3].

  • Dissertation Defense: "Novel Optical Techniques for Probing Orbital and Spin Angular Momentum in Solids"

    DRL, Room 4C8

    Mehmet Noyan

  • Particle Physics seminar: "First results from the PROSPECT reactor neutrino experiment"

    David Rittenhouse Laboratory, 4N12

    Danielle Norcini, Yale University

    Experiments at nuclear reactors have played a key role in determining the properties of the weakly-interacting neutrinos. Results from recent reactor experiments suggest a disagreement between the observed antineutrino flux and energy spectrum when compared to predictions. Beyond the Standard Model sterile neutrinos and corrections to complex nuclear models have been posed to explain the discrepancy. To address this physics, the PROSPECT experiment precisely measures antineutrino energy spectra at multiple, very short baselines (< 10m) from the High Flux Isotope Reactor.

  • High Energy Theory seminar: "Axion couplings and implications for cosmology and astrophysics"

    David Rittenhouse Laboratory, 2N36

    JiJi Fan, Brown University

    Many cosmological models rely on large couplings of axions (pseudo-scalar fields) to gauge fields. Examples include theories of magnetogenesis, inflation on a steep potential, chiral gravitational waves, and chromonatural inflation.

  • Department Colloquium: "UNITED STATES OF AMERICA v. XIAOXING XI: Why It Matters"

    David Rittenhouse Laboratory, A8

    Xiaoxing Xi, Temple University

    As Interim Chair of Temple University’s Physics Department, I was busy on May 20, 2015 with my class, research, promotion of colleagues, and a university task force I was chairing. I gave a dinner-time lecture for Pint of Science, a science festival, at an Irish pub before picking up my wife at the airport, who was returning from an overseas trip. My elder daughter was home from college for a few days. We made a plan to visit a famous Korean fried chicken restaurant.

  • Penn Science Cafe: "The Physics of Foam"

    Suzanne Roberts Theater, 2nd Floor Lobby, 480 South Broad Street, Philadelphia

    Douglas Durian, University of Pennsylvania

    It's easy to foam up soapy water but not to understand the surprising properties of foam. How can it be white and solid when it's made mostly of gas and a little liquid, neither of which is white or solid? Douglas Durian will explain how foams change over time and some of the excitement they offer as a modern research topic in fundamental physics and mathematics.

  • High Energy Theory Seminar: "SYK, harmonic analysis, and multipoint conformal blocks"

    David Rittenhouse Laboratory, 2N36

    Vladimir Rosenhaus, IAS, Princeton University

  • Condensed Matter Seminar: "Soft complexity in gels: network connectivity, viscoelasticity and failure"

    David Rittenhouse Laboratory, A6

    Emanuela Del Gado, Georgetown University

    Soft matter (colloids, polymers, proteins…) often self-assembles into gels with diverse structure and mechanics, ubiquitous in nature and extensively used to improve diverse industrial products, where they provide texture, softness, and stability. Through the interplay between their microstructure with an imposed deformation, they can be stretched, flow, squeezed or fractured, but controlling and being able to design such processes (think for example to soft inks for 3D printing technologies) requires a fundamental understanding that is still lacking.

  • Astronomy seminar: "Using the environment to infer supernova progenitor properties"

    David Rittenhouse Laboratory, A6

    Lluis Galbany, University of Pittsburgh

    Integral Field Spectroscopy (IFS) applied to supernova (SN) environmental studies have shown the potential of this technique to directly characterize the galactic environmental parameters at SN locations, compare them to those at different locations of the galaxy, and put constraints on progenitor stars for different SN types. In this talk, I will summarize current efforts from the PISCO compilation, Hi-KIDS, MaNGA, and the AMUSING surveys, that have put together more than 500 SN hosts observed with IFS, and give details about published results from these datasets. 

  • High Energy Theory Seminar: "Gauge-field inflation and the origin of the matter-antimatter asymmetry"

    David Rittenhouse Laboratory, 2N36

    Peter Adshead, University of Illinois, Urbana Champaign

    In this talk, I  describe a new class of inflationary scenarios which utilize gauge fields to generate inflationary dynamics in the early universe. Beyond simply providing yet another model for inflation, these scenarios furnish unique observational imprints which distinguish them from standard scalar-field scenarios.