Past Events

  • Astro Seminar: "Exodynamos: Magnetic Field Generation and Detectability"

    David Rittenhouse Laboratory, A4


    Planetary magnetic fields are ubiquitous in the Solar System and extrasolar planets are common in the galaxy.  However, no extrasolar planetary magnetic field (or exodynamo) has yet been directly detected. Magnetic fields offer a unique window into the internal structure and dynamics of planets, can be remotely detected by electron cyclotron emission at radio wavelengths, and are commonly assumed to be important for surface habitability.

  • Condensed Matter seminar: "Braiding Light"

    David Rittenhouse Laboratory, A4

    Claudio Chamon, Boston University

    Many topological phenomena first proposed and observed in the context of electrons in solids have recently found counterparts in optical and acoustic systems. In this talk I will discuss non-Abelian Berry phases that can accumulate when coherent states of light are injected into “topological guided modes” in specially-fabricated photonic waveguide arrays. These modes are photonic analogues of topological zero modes  in electronic systems.

  • Astro Seminar: "Beyond Pluto: The Hunt for Planet X"

    David Rittenhouse Laboratory, A4

    Scott Sheppard (Carnegie Institution for Science)

    The Kuiper Belt, which has Pluto as the largest member, is a region of comet like objects just beyond Neptune.  This belt of objects has an outer edge, which we are now only able to explore in detail.  For the past few years we have been performing the largest and deepest survey ever obtained to search for distant solar system objects.

  • Dissertation Defense: "Hard-, Soft- and Sticky Spheres for Dynamical Studies of Disordered Colloidal Packings"

    LRSM, Reading Room

    Matthew Gratale (UPenn)

  • High Energy Theory: "Effective Field Theory of Dissipative Fluids"

    David Rittenhouse Laboratory, 2N36

    Hong Liu (MIT)

  • ABO Seminars: "Label-free Optical Micro Imaging of Tissue Histology in Vivo"

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

    Xingde Li (Johns Hopkins University)

    This seminar will focus on our recent progresses on developing high-resolution biophotonic imaging technologies, particularly the second-generation optical coherence tomography (OCT) endoscopy and multiphoton endomicroscopy. These technologies have shown significant translational potential for imaging tissue microanatomies in vivo at a resolution approaching or at standard histopathology but without the need for tissue removal, staining or processing.

  • Department Colloquium: "The Universe as a Lab for Fundamental Physics: Results from Spider and Future Suborbital Missions"

    David Rittenhouse Laboratory, A8

    William Jones (Princeton) Hosted by James Aguirre

    I will describe our recent results from observations of the Cosmic Microwave Background, including a status report on the recent flight of the Spider experiment, a balloon borne CMB polarimeter.  I will also discuss a convergence of observational needs and technological capabilities that provide intriguing opportunities for improving our understanding of both the late- and early-time evolution of the Universe.


    *Refreshments served @ 3:30pm, DRL 2nd Floor Faculty Lounge*

  • Condensed Matter seminar: "Wavefront Shaping for in vivo Brain Imaging"

    David Rittenhouse Laboratory, A4

    Na Ji, Janelia Research Campus

    There are about the same number of stars in our galaxy as there are neurons in our brain. To study stars and neurons using optical imaging, we face similar challenges of image degradation by aberrations and scattering. Adaptive optics, a form of wavefront shaping, has revolutionized astronomy by allowing ground-based telescopes to obtain high-resolution images of stars through Earth's turbulent atmosphere. Applying wavefront shaping to brain imaging is similarly beneficial.

  • Condensed Matter seminar: “Do entangled polymers possess a shear banding instability?”

    David Rittenhouse Laboratory, A4

    Peter Olmsted, Georgetown University

    The original Doi-Edwards theory (1978) predicted that long entangled polymers should become unstable to homogeneous shear flow for shear rates exceeding the relaxation (reptation) time. At the time this seemed to explain a number of instabilities seen in polymers. However, over the years those instabilities have been explained in other ways, as physics that was left out of the original theory was incorporated into the model. New experiments, however, suggest that the original Doi-Edwards instability could be valid after all.

  • Astro Seminar: "A Possible First Detection of High-Redshift Population III Stars"

    David Rittenhouse Laboratory, A4

    Eli Visbal (Columbia)

    The recent observation of CR7 (Sobral et al. 2015), the brightest Lyman-alpha emitter at z~7, could be the first detection of Pop III stars (i.e. stars formed from primordial/extremely metal-poor gas). CR7 has strong He II 1640 angstrom line emission and no detected metal lines, as predicted for Pop III stars. However, the He II line luminosity corresponds to ~10^7 solar masses of Pop III stars, and such a large Pop III star cluster is generally be expected to be metal-enriched from previous star formation.