Past Events

  • Department Colloquium *Special*: "Solving the Solar Neutrino Problem"

    David Rittenhouse Laboratory, A8

    Joshua Klein (UPenn) Hosted by Gene Beier

    We will discuss the work of the Sudbury Neutrino Observatory, and the Penngroup in particular, that provided the solution to the long-standing Solar Neutrino Problem and which has been recognized this year by the Nobel Prize and the Breakthrough Prize. Some discussion of the implications of thesemeasurements and future directions will also be presented.

  • Rittenhouse Lecture:" Expansion of the Universe seen by Hubble"

    David Rittenhouse Laboratory, A8

    Adam Reiss (JHU/STScI) Hosted by Adam Lidz

    The Hubble constant remains one of the most important parameters in the cosmological model, setting the size and age scales of the Universe.  Present uncertainties in the cosmological model including the nature of dark energy, the properties of neutrinos and the scale of departures from flat geometry can be constrained by measurements of the Hubble constant made to higher precision than was possible with the first generations of Hubble Telescope instruments.  Streamlined distances ladders constructed from infrared observations of Cepheids and type Ia supernovae with ruthle

  • 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.

  • Physics Department Colloquium: "Fluid 'Ratchets' and Biological Locomotion"

    DRL A8

    Jun Zhang (NYU-Courant Institute)

    In this talk, I will discuss a few laboratory experiments that were inspired from examples of biological locomotion. There, solid structures were forced to interact with their surrounding fluid. These structures, or dynamic boundaries, interact with fluid in asymmetric fashions - either because of their anisotropic geometry or by the spontaneous breaking of symmetry in their response to the fluid. When subject to reciprocal forcing, the coupled systems behave in ways that can be described as 'fluid ratchets'.

  • Evolution Colloquium: "How Much Sex is Enough?"

    Carolyn Hoff Lynch Lecture Hall Chemistry Building, 231 S. 34th Street

    Professor Daniel S. Fisher (Stanford University)

    Sexual reproduction has many costs--especially the existence of lots of males, but sex, or more generally exchange of DNA is widely believed to have major advanages for evolution. Yet most of the arguments are rather qualitative: with multiple large and small numbers involved in evolutionary processes, quantitative understanding is essential...


    **Light Refreshments served @ 2:30pm**

  • The Henry Primakoff Lecture: Was Einstein Right? A Centennial Assessment

    DRL A8

    Clifford Will (University of Florida)

    A century after Einstein's formulation of general relativity, a remarkably diverse set of precision experiments has established it as the ``standard model'' for gravitational physics.   Yet it might not be the final word.  We review the array of measurements that have verified general relativity in the laboratory, in the solar system and in binary pulsars.   We then describe some of the opportunities and challenges involved in testing Einstein's great theory in strong-field regimes, in gravitational waves, and in cosmology.

  • Department Colloquium: "Inflationary Cosmology & Mythology"

    David Rittenhouse Laboratory, A8

    Paul Steinhardt (Princeton)

    This talk will present an unvarnished assessment of inflationary cosmology in light of cosmological observations, making clear the difference between the facts and the myths and enabling a fair scientific

  • Department Colloquium: Einstein and Quantum Mechanics: It’s Not What You Think

    David Rittenhouse Laboratory A8 Refreshments available in DRL 2nd floor Faculty Lounge @ 3:30pm

    Douglas Stone, Yale

    Einstein is well known for his rejection of quantum mechanics in the form it emerged from the work of Heisenberg, Born and Schrodinger in 1926.  Much less appreciated are the many seminal contributions he made to quantum theory prior to his final scientific verdict: that the theory was at best incomplete.  In this talk I present an overview of Einstein’s many conceptual breakthroughs and place them in historical context.  I argue that Einstein, much more than Planck, introduced the concept of quantization of energy in atomic mechanics.

  • Department Colloquium: Restoration of Early Sound Recordings using Optical Metrology and Image Analysis


    Carl Haber, LBL

    Sound was first recorded and reproduced by Thomas Edison in 1877.  Until about 1950, when magnetic tape use became common, most recordings were made on mechanical media such as wax, foil, shellac, lacquer, and plastic.  Some of these older recordings contain material of great historical interest, may be in obsolete formats, and are damaged, decaying, or are now considered too delicate to play.

  • Department Colloquium: "Topological Boundary Modes from Quantum Electronics to Classical Mechanics"


    Professor Charles Kane (Univ of Penn)

    Over the past several years, our understanding of topological electronic phases of matter has advanced dramatically.