Semester Seminar Chair - Professor Jim Eckstein: eckstein@physics.uiuc.edu

For advance arrangements on speaker's visit schedule, contact Peggy Pennell: ppennell@uiuc.edu

For Fall 1998 schedule, click here.

UIUC - Dept. of Physics

Laboratory for Fluorescence Dynamics

Department of Astronomy and Astrophysics - University of Chicago

UIUC - Dept. of Physics

UIUC - Dept. of Physics

Jefferson National Accelerator Lab

UIUC - Dept. of Elec. and Comp. Engr.

Sun Microsystems

UIUC - D.B. Willett Professor of Materials Science and Head, Electronic Materials Division

Tage Erlander Professor of Physics, Linköping Univ. (Sweden)

Brookhaven National Lab

Dept. of Physics - Stanford University

Dept. of Physics - Univ. of Rochester

Almaden Research Center - IBM Corp.

In this talk, I will review some of the most recent advances in STM measurements, from attempts to identify individual adsorbates, to experiments probing the spatial variations of superconductivity and its interaction with magnetism. The new capabilities made possible by its operation at low temperatures and ultra-high vacuum make the STM experiments a testing ground for some of the fundamental ideas in condensed matter physics. 

The very high peak power and repetition rate of a new class of pulsed laser introduced about 5 years ago opened the possibility of easy access to multiphoton excitation in spectroscopy and microscopy. New experiments are today feasible and quantitative spectroscopy in a cell is a step closer. I will describe our implementation of a new kind of microscope which permits the investigation of kinetic processes in living cells which were difficult or impossible to study without multiphoton excitation.

"Cosmology Solved?"

The discovery of the cosmic microwave background (CMB) in 1964 by Penzias and Wilson led to the establishment of the hot big-bang as the standard cosmological model some ten years later. Discoveries made in 1998 may ultimately have as profound an effect on our understanding of the origin and evolution of the Universe. Taken at face value, they confirm the basic tenets of Inflation + Cold Dark Matter, a theory that addresses all the fundamental questions left unanswered by the hot big-bang model. Just as it took a decade to establish the hot big-bang model after the discovery of the CMB, it will likely take another ten years to establish the latest addition to the standard cosmology. Whether or not 1998 proves to be a cosmic milestone, the coming avalanche of high-quality cosmological data promises to make the next twenty years an extremely exciting period for cosmology.

"The First Hundred Years of Electronic Structure"

From the discovery in 1897 to the present electronic structure has played a special role in physics. In the first two decades of this century, the properties displayed by electrons in atoms, molecules, and condensed matter presented baffling mysteries completely inexplicable in classical physics: metallic conductivity, superconductivity, magnetism, just to name a few. From the famous model for hydrogen Niels Bohr to the new quantum theory of 1923-1925, electrons were the testing ground for enormous creative activity. This talk will describe some of the key people and steps in this history, with emphasis upon the role in condensed matter physics[1,2]: the development of the early fundamental ideas in the 1920's; practical methods in the 1930's; the advent of computers in the post-war years; and more modern developments in theory and practice. We will mention especially the two theoretical approaches that have had great impact in the latter half of the century: Fermi Liquid Theory of Lev Landau and others, and Density Functional Theory of Walter Kohn and others. Just to give one example of the practical importance, the world was changed by the work of John Bardeen and William Shockley, whose thesis research was theoretical calculations of electronic structure under the direction of Wigner and Slater, respectively. [1] This work is part of the preparation of a Wall Chart Time Line for the History of Electronic Structure to be exhibited at the 1999 APS Centennial Meeting. It is NOT meant to be complete since there are other charts on magnetism, strongly-correlated systems, superconductivity, etc. (A preliminary version (with errors) is on display in the MRL near room 2007.)

"Nanometer Resolution, Single-molecule Sensitivity with Visible Light:

Application to Muscle (Actomyosin) and Nerves (Ion-Channels)"

Biological molecules are typically 1-10 nanometer in size, several orders of magnitude smaller than the classical diffraction limit of far-field optics using visible light. Yet visible-light techniques -specifically fluorescence- offer exquisite sensitivity and selectivity for probing biomolecules. We have recently made two different but related advances to a technique called fluorescence resonance energy transfer (FRET), which relies on the near-field dipole-dipole coupling of two fluorescent or luminescence dyes that can be site-specifically placed on biomolecules. Sub-nanometer resolution and single-molecule sensitivity can now be achieved using visible light. One of the advances relies on the highly unusual spectroscopic properties of luminescent lanthanide ions; the other advance relies on recent improvements in single-molecule detection methods. We have applied the lanthanide-based technique to the study of muscle contraction and nerve conduction at the molecule level. Specifically, we have detected shape changes in the actomyosin protein-complex that help explain how muscle contracts, and we have detected shape changes in the Shaker potassium ion channel that help explain the voltage-dependence of nerve conduction.

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No Seminar - Spring Vacation

No Seminar - APS March Meeting

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