| All seminars are on Wednesdays at 4 - 5 pm in WGR 304 unless otherwise noted | ||
|---|---|---|
| DATE | SPEAKER | TITLE |
| 10 January |
David McIntyre OSU Physics |
Optical Trapping and Manipulation of Atoms and Particles Abstract |
| 17 January | Heiner Linke UO Physics | Thermoelectric Effects in Nanowires http://www.uoregon.edu/~linke/ |
| 24 January | Alexey Shvarev OSU Chemistry | Ion-Selective Sensors: New Frontiers |
| 31 January | David Foster Deep Photonics | Methods for Numerical Beam Propagation in Nonlinear Media |
| 7 February | Thomas Mossberg LightSmyth Technologies, Inc. | Harnessing Deep UV Photolithography for Free-Space and Integrated Photonics |
| 14 February | Raghuveer Parthasarathy UO Physics | Spatial Organization of, at, and by Membranes Abstract http://physics.uoregon.edu/~raghu/ |
| 21 February | John Toner UO Physics | Squeezing Superfluid from a Stone: Coupling Superfluidity and Elasticity in a Supersolid Abstract |
| 28 February | Grad students | APS Practice talks |
| 7 March | March APS meeting | No seminar? |
| 14 March |
Fred Moore Whitman College / UO |
Vibrational Sum Frequency Spectroscopy of Aqueous Interfaces - a dilettante's view of six year's work |
| Seminars are open to all; it is not necessary to register to attend! Students who wish to take the seminar series for credit should register for one of PH607 CRN 21423; PH607 CRN 21424; PH507 CRN 21416; PH507 CRN 21417. The 2-credit versions are for those who will present a talk during the seminar series. | ||
| 10 January: Optical Trapping and Manipulation of Atoms and Particles Abstract: Optical interactions with matter involve energy exchange and momentum exchange. The momentum aspect gives rise to strong optical forces that can be used to manipulate and control the positions and velocities of atoms and particles. I will review the basic physics of this field and our work on laser cooling and trapping of rubidium atoms. I will then discuss our new effort to trap particles using a strongly focused laser beam in an optical tweezers trap. Work to date has concentrated on micron sized particles, but we are working towards trapping smaller nanoparticles. New experiments and potential applications will be discussed. Return to top |
| 14 February: Spatial Organization of, at, and by Membranes Abstract: Cellular membranes are remarkable materials - flexible, heterogeneous, two-dimensional fluids whose spatial organization is crucial to many biophysical processes. Little is known about the mechanisms that maintain various modes of organization, and this talk will explore some recent experiments on this theme. First, I'll discuss lipid membranes that phase-separate into coexisting fluid phases - widely believed to mimic phase-separation tendencies in membranes in vivo - and ask how the locations of the various phases can be controlled. Assisted by microfabricated surfaces that direct membrane curvature, we find that curvature and phase separation are closely connected, and that curvature can control the locations of phase-separated domains. Next, we examine molecules that mimic mucins, a class of large "brush-like" membrane-anchored proteins that are believed to project outward from cell surfaces to better interact with their environment. Using interferometric imaging techniques, we determine the molecular orientation of these mucin mimics, raising questions about the mechanisms that control cell-surface protein organization. Finally, we ask whether the physical properties of membranes might be of use in creating and organizing new, non-biological materials, and discuss a nascent project involving optical traps to probe membrane-mediated colloidal crystallization. Return to top |
| 21 February: Squeezing Superfluid from a Stone: Coupling Superfluidity and Elasticity in a Supersolid Abstract: Superfluidity - the ability of liquid 4He, when cooled below 2.176 K, to flow without resistance through narrow pores - is one of the most amazing phenomena in physics. Supersolidity - the coexistence of superfluid behavior with the crystalline order of a solid - was proposed theoretically long ago as an even more exotic phase of solid 4He, but it has eluded detection until recently. In 2004, Kim and Chan (E. Kim and M. H. W. Chan, Nature (London) 427, 225 (2004); E. Kim and M. H. W. Chan, Science 305, 1941 (2004).) reported the onset of "nonclassical rotational inertia" in a torsional oscillator experiment with solid 4He, and they interpret their results as indicating the onset of supersolidity. In this talk, I'll describe what a supersolid is, discuss the Chan et al experiments (in the process revealing how to tell a raw from a hard boiled egg), and present the theory I've recently developed (with Paul Goldbart of University of Illinois at Urbana-Champaign, and Alan Dorsey of University of Florida) of the normal solid to supersolid (NS-SS) phase transition. Return to top |
| Information for speakers: Weniger 304 has a Windows-based computer running Powerpoint 2003, Acrobat Reader 6.0, and Internet Explorer. There may be other software that you could use if you need it - ask your host. The computer is connected to the internet, and to a projector. It has a USB interface. Thus your talk could be on a USB drive, or (riskier!) accessible via internet on your home computer. You may also bring your own laptop to connect to the projector (Mac users, be sure to have the correct adaptor). There is also an overhead projector and a chalkboard. On campus visitors: Weniger Hall (Physics) is located on Monroe Avenue between Gilbert Hall (Chemistry) and the Student Health Center. WGR 304 is on the 3rd floor on the east side of the building. Off campus visitors: Parking is available in the lots on the west side of Weniger, and is usually plentiful in the afternoons. A permit is required, so please ask the host to obtain one for you (OSU parking permits are reciprocal with the U of O and OSU Cascades campus). There is also metered city parking on Monroe Avenue. Weniger Hall is at the junction of N.W. Monroe Avenue and 23rd Street. In Corvallis, the following rules are generally good around the university: Numbered streets run north-south starting at 1st street in the east to 53rd in the west. President streets are in chronological order and run east-west starting with Washington in the south. Highway 34 from I-5 (take exit 228) brings you in at 2nd Street and Harrison. Highway 99W becomes 3rd Street when you enter town from the south, and Highway 99W becomes 4th Street when you enter from the north. Campus map. Return to top |
