Past Events

  • Condensed Matter seminar: "The crumpled state: crumpling dynamics and the evolution of damage networks"

    David Rittenhouse Laboratory, A4

    Shmuel Rubinstein, Harvard University

    The simple process of crumpling a sheet of paper with our hands results in a complex network of interconnected permanent creases of many sizes and orientations. Sheet preferentially bends along these creases, introducing history dependence to the process of crumpling. I will present an experimental study of the dynamics of crumpling. Specifically, I will first discuss how a crease network evolves when a thin elastoplastic sheet is repeatedly crumpled, opened up and then re-crumpled.

  • Astro Seminar: "The Cosmology Large Angular Scale Surveyor (CLASS)"

    David Rittenhouse Laboratory, A4

    David Chuss (Villanova)

    The LCDM model of cosmology has been successful in describing the universe’s energy content and evolution with six parameters; however, the observed geometric flatness of the universe, its near homogeneity, and the small deviation from scale invariance derived from the temperature anisotropy of the cosmic microwave background (CMB) have hinted that the universe underwent an inflationary epoch in its infancy.  Cosmic inflation is predicted to produce a background of gravitational waves that would polarize the CMB in a distinct pattern.

  • Math-Bio seminar: "Assessing the relationship of ancient samples to modern populations and to each other"

    318 Carolyn Lynch Laboratory

    Joshua Schraiber, Temple University

    When ancient samples are sequenced, one of the first questions asked is how those samples relate to modern populations and to each other. Commonly, this is assessed using methods such as Structure or Admixture, which model individuals as mixtures of latent "ancestry components". If an ancient individual is found to not carry similar ancestry components to a modern individual, that sample is considered to be not directly related to the modern individual.

  • Math-Bio seminar: "Bayesian inference of evolutionary divergence with genomic data under diverse demographic models"

    318 Carolyn Lynch Laboratory

    Yujin Chung, Temple University

    In the study of diverging populations and species, a common goal is to disentangle the conflicting signals of prolonged genetic drift (elevating divergence) and gene exchange (removing it). In this talk, I present a new Bayesian method for estimating demographic history using population genomic samples. Several key innovations are introduced that allow the study of diverse models within an Isolation with Migration framework.

  • High Energy Seminar: "TBA"

    David Rittenhouse Laboratory, 2N36

    Paolo Creminelli (ICTP)

  • Special Seminar: "Steric association of bent molecules into chiral oligomeric chains: the slinky-like structure of the twist-bend nematic phase"

    David Rittenhouse Laboratory, A4

    Noel Clark, University of Colorado

  • Dissertation Defense: "Transport Signatures of Quantum Phase Transitions and the Interplay of Geometry and Topology in Nodal Materials"

    David Rittenhouse Laboratory, 3N1H

    Benjamin Wieder

  • Department Colloquium:"The Maps Inside Your Head"

    David Rittenhouse Laboratory, A8

    Vijay Balasubramanian (UPenn) hosted by: Joe Kroll

    How do our brains make sense of a complex and unpredictable world? In this talk, I will discuss a physicist's approach to the neural topography of information processing in the brain. First I will review the brain's architecture, and how neural circuits map out the sensory and cognitive worlds. Then I will describe how highly complex sensory and cognitive tasks are carried out by the cooperative action of many specialized neurons and circuits, each of which has a simple function. I will illustrate my remarks with one sensory example and one cognitive example.

  • Astro Seminar: "The New Ly-alpha Power Spectrum Measurements and constraints on WDM"

    David Rittenhouse Laboratory, A4

    Vid Irsic (University of Washington)

    With the X-Shooter XQ-100 Legacy survey, 100 QSO measurements at intermediate resolutions were available to measure the Lyman-alpha power spectrum in the similar redshift range to SDSS (z=3 - 4.2), but to smaller scales (k_max ~ 6 h/Mpc). I will present these new results and comment on the data-analysis procedure. In the second part of the talk I will focus on using these new data (along with high-resolution high-redshift data) to put constraints on the cosmological and astrophysical parameters, and to review the constraints on the mass of a WDM particle as a DM candidate.

  • Dissertation Defense: "Understanding the Implications of Neural Population Activity on Behavior"

    David Rittenhouse Laboratory, 3W2

    John Briguglio (UPenn)