Past Events

  • High Energy Theory Seminar: "TBA"

    DRL 2N36

    Cliff Burgess (McMaster)

  • ABO Seminars: "TBA"

    Donner Building 3400 Spruce Street Donner Auditorium, Basement *Pizza served at 11:45am*

    Regine Choe (University of Rochester)

  • Condensed Matter Seminar: "Clogging and anti-clogging in biological networks"

    David Rittenhouse Laboratory, A4

    Marcus Roper (UCLA)

    Clogging, or congestion, is usually assumed to be the enemy of efficient transport, and a lot of energy is expended by human engineers to eliminate or tame clogging in transport networks -- whether they carry fluid, data or cars. In this talk I will describe two examples of biological transport networks, in which the potential for clogging exists. In the first example, flow regulation completely eliminates clogging. In the second clogging is intentfully triggered, suggesting that Nature's attitude to clogging may be more nuanced than we previously realized.

  • Astro Seminar: "The Challenge of Predicting the Clustering of Matter in the Era of High-Precision Cosmology"

    David Rittenhouse Laboratory, A6

    Pier Stefano Corasaniti (LUTH, Observatoire de Paris)

    In the future a new generation of galaxy surveys will probe the cosmic distribution of matter across an unprecedented range of scales and redshifts potentially shedding new light on the nature of the invisible components in

  • Math-Bio seminar: "The Evolution of Distributed Sensing and Collective Computation in Animal Populations"

    Carolyn Lynch Laboratory, room 318

    George Hagstrom, Department of Ecology & Evolutionary Biology, Princeton University

    Many animal groups exhibit rapid, coordinated collective motion. Yet, the evolutionary forces that cause such collective responses to evolve are poorly understood. Here we develop analytical methods and evolutionary simulations based on experimental data from schooling fish. We use these methods to investigate how populations evolve within unpredictable, time-varying resource environments.

  • Dissertation Defense: "A Structural Perspective on Disordered Solids"

    David Rittenhouse Laboratory, 4E9

    Sam Schoenholz (UPenn)

  • Department Colloquium: "Challenges for Cosmology on Galaxy Scales"

    David Rittenhouse Laboratory, A8

    Benoit Famaey (Strasbourg Observatory)

    While there is indisputable observational evidence for a new degree of freedom behaving as a collisionless fluid of particles on large scales, i.e. dark matter, there is no such solid evidence on galaxy scales. On the contrary, the current standard model of cosmology is plagued with numerous challenges at these scales, which we review here.

  • Math-Bio seminar: "Local Shape from Shading with a Generic Constraint"

    Carolyn Lynch Laboratory, room 318

    Benjamin Kunsberg, Brown University

    Humans have a remarkable ability to infer shape from shading (SFS) information. In computer vision this is often formulated with a Lambertian reflectance function, but it remains under-posed and incompletely solved.  Abstractly, the intensity in an image is a single valued function and the goal is to uncover the vector valued normal function. This ill-posedness has resulted in many proposed techniques that are either regularizations or propagations from known values. Our goal is to understand, mathematically and computationally, how we solve this problem.

  • Astro Seminar: "Probing Dark Energy with the Canadian Hydrogen Intensity Mapping Experiment (CHIME)"

    David Rittenhouse Laboratory, A6

    Richard Shaw (University of British Columbia)

    CHIME will use the 21cm emission line of neutral hydrogen to map large-scale structure between redshifts of 0.8 and 2.5. By measuring Baryon Acoustic Oscillations (BAO) we will place constraints on the dark energy equation of state as it begins to dominate the expansion of the Universe, particularly at redshifts poorly probed by current BAO surveys.

  • Professor Gary Gibbons: "Introduction to Supergravity"

    DRL 2C6

    Gary Gibbons, Visiting Distinguished Professor (Cambridge, UK)

    Supergravity is a theory of gravity incorporating a super-symmetry", that is a symmetry between Fermions and Bosons. The boson in question is the graviton which carries spin 2 and its fermionic partner is the gravitino which carries spin 3/2. The first is governed classically by Einstein's equations and the second by the Rarita-Schwinger equations.