Events at Physics |
Events During the Week of October 11th through October 18th, 2009
Monday, October 12th, 2009
- Plasma Physics (Physics/ECE/NE 922) Seminar
- Laboratory Simulations of Astrophysical Jets and Solar Coronal Loops
- Time: 12:05 pm
- Place: 4274 Chamberlin Hall
- Speaker: Paul Bellan, Cal Tech
- R. G. Herb Condensed Matter Seminar
- Special Date and Time
- Weak compressibility of surface wave turbulence
- Time: 2:30 pm
- Place: 5310 Chamberlin
- Speaker: Marija Vucelja, Weizmann Institute of Science
- Abstract: Clustering of matter on the surface of lakes and pools and of oil slicks and seaweed on the sea surface is well-known empirically but there is no theory that describes it. Since surface flows are always compressible, such a theory should be based on the description of the development of density of inhomogeneities in a compressible flow. We studied the growth of small-scale inhomogeneities in the density of particles floating in weakly nonlinear small-amplitude surface waves. Despite the small amplitude, the accumulated effect of the long-time evolution may produce a strongly inhomogeneous distribution of the floaters: density fluctuations grow exponentially with a small but finite exponent. We have shown that the exponent is of sixth or higher order in wave amplitude. As a result, the inhomogeneities do not form within typical time scales of the natural environment. Thus the turbulence of surface waves is weakly compressible and alone it cannot be a realistic mechanism of the clustering of matter on liquid surfaces. However if besides waves there are also currents, the interplay of waves with currents, might be in some cases responsible for the patchiness of the floaters.
- Host: Susan Coppersmith
- High Energy Seminar
- MiniBooNE Oscillation Results and the Sterile Neutrino Mystery
- Time: 4:00 pm - 5:00 pm
- Place: 4274 Chamberlin
- Speaker: Georgia Karagiorgi, Massachusetts Institute of Technology
- Abstract: MiniBooNE is a short-baseline experiment located at Fermilab, sensitive to muon
(anti)neutrino to electron (anti)neutrino appearance and muon (anti)neutrino
disappearance oscillations at high $Delta m^2sim$ 1 eV$^2$. These oscillation
searches have been motivated by the 3.8$sigma$ excess of electron antineutrino
events in a muon antineutrino beam observed by the LSND experiment in 1995. In
this talk, recent antineutrino and updated neutrino oscillation results from
MiniBooNE will be presented, and implications for the LSND excess will be
discussed within the context of sterile neutrino oscillation models.
- Host: Matthew Herndon
Tuesday, October 13th, 2009
- Chaos & Complex Systems Seminar
- Conjectures on music, artistry and the brain
- Time: 12:05 pm
- Place: 4274 Chamberlin (Refreshments will be served)
- Speaker: Russell Gardner, UW Department of Psychiatry
- Abstract: George Steiner tells that "... we write about books or about music or about art because 'some primary instinct of communion' would have us share with and communicate to others an overwhelming enrichment..." He felt this in 1959 with his first major writing and it remained his conviction. I find it resonates, yet how does it work? What does "instinct" mean in terms of the brain? I am not a musician and though always finding music a pleasure and most interesting challenge, I have felt the reasons mysterious ones. Why do people perform? Why do people listen? Where and how in the brain does art generally and music specifically gain its place in humans? What I will say hinges on various recent readings and on communications for the past two years with fellow members of the Arts Immersion (AIm) group. Plus, present some ideas on the medial temporal lobes that bear on performance issues and on evolutionary biology as these bear on human communication. I hope to address how do "artistic" people - including musicians - compare and contrast with other people? How does the musical communication share features of other communications and how may it stand unique? How does it compare/contrast with other means of artistic expression? How does sound production and appreciation in non-human animals bear on the subject? <br>
<br>
Gardner, Howard: In search of the Ur-song. In Gardner, Howard: Art Mind & Brain: A Cognitive Approach to Creativity. New York, NY: Basic Books, Inc., 1982. <br>
Levitan, Daniel J. This is Your Brain on Music: The Science of a Human Obsession. NY: Plume Penquin, 2006. <br>
Mithen, Steve: The Singing Neanderthals: The Origins of Music, Language, Mind and Body. Cambridge, MA: Harvard University Press, 2006. <br>
Sacks O: Musicophilia: Tales of Music and The Brain. NY: Knopf, 2007. <br>
Steiner, George: Introduction, A Reader. OUP, 1984, p.7. - Astronomy Colloquium
- Infrared Studies of Young Brown Dwarfs
- Time: 3:30 pm - 5:00 pm
- Place: 3425 Sterling Hall
- Speaker: Katelyn Allers, Bucknell University
- Abstract: Brown dwarfs (objects with masses too low to sustain hydrogen burning) are the bridge between planets and stars. Young brown dwarfs are particularly exciting as objects with masses in the range of extrasolar planets are within in reach of direct observations in the near and mid-infrared. These objects can provide a laboratory for detailed quantitative study in a context where light from a parent star does not mask the source properties of the planetary-mass object. In the past decade, young brown dwarfs have been found with increasing frequency, though planetary-mass brown dwarfs have remained largely elusive. Only a handful of potential planetary-mass brown dwarfs are known, but the intrinsic faintness of these objects and the uncertainty in evolutionary models makes determining their masses and ages very difficult. In this talk, I will describe two new and efficient methods for finding planetary-mass brown dwarfs. I will also discuss ways in which we can test evolutionary models of brown dwarfs using large spectroscopic databases and high resolution imaging.
- Host: Professor Amy Barger
Wednesday, October 14th, 2009
- MIT Lincoln Labs Recruitment Presentation
- MIT Lincoln Labs Seminar/Info-session
- Time: 6:00 pm
- Place: 4274 Chamberlin Hall
- Speaker: Matt Vanderhill, Ph.D., MIT Lincoln Laboratory
- Abstract: You are cordially invited to come to 4274 Chamberlin Hall on Wednesday evening, October 14, 2009, starting at 6:00 pm to learn about employment opportunities for you at Lincoln Laboratory. Lincoln is a federal research and development center* operated by the Massachusetts Institute of Technology that conducts a wide variety of applied and basic research in such areas as advanced electronic and optical materials, space and terrestrial surveillance, communication systems, radar and optical systems technology, air traffic control, and air and missile defense technology. The informal seminar will include an overview of the current research programs and will answer questions about working at Lincoln and living in the Boston and New England area. Whether your employment plans are nearly complete or just starting to be formed, you are invited to come to this informal presentation. Refreshments will be served. *U.S. Citizenship is required for employment.
- Host: Jane Schimmel
Thursday, October 15th, 2009
- NPAC (Nuclear/Particle/Astro/Cosmo) Forum
- The Search for the Schwinger Effect: Nonperturbative Vacuum Pair Production
- Time: 4:00 pm
- Place: 4274 Chamberlin
- Speaker: Gerald Dunne, University of Connecticut
- Abstract: The fact that the QED vacuum is unstable via the production of
electron-positron pairs in the presence of an external electric field is one of the first non-trivial predictions of QED, due to Heisenberg and Euler, and later formalized by Schwinger. This non-perturbative effect has implications and analogies in QCD and gravitational physics. However, the effect is so weak that it has still not been directly observed. But recent experimental progress in ultra-intense laser systems has brought us
tantalizingly close to seeing this non-perturbative particle production. I will review the current status and describe some new theoretical ideas aimed at making this process accessible. - Host: Michael Ramsey-Musolf
- Introductory Graduate Seminar
- Condensed Matter Experimental
- Time: 5:30 pm
- Place: 2223 Chamberlin Hall
- Speaker: Eriksson, Himpsel, Lagally, McDermott, Onellion, Rzchowski, Winokur, University of Wisconsin Department of Physics
Friday, October 16th, 2009
- Theory/Phenomenology Seminar
- Extending the Higgs Effective Theory
- Time: 2:30 pm - 3:30 pm
- Place: 5280 Chamberlin Hall
- Speaker: Duff Neill, Carnegie Mellon University
- Abstract: For the LHC and Tevatron the Higgs Effective Theory from integrating out
the top quark has done a remarkable job with only the leading operator HFF
as the basis for calculating the higgs production rates. But for certain
observables the effective operator approximation can begin to break down.
Either one can just calculate in the full theory, or extend the effective
theory with higher dimensional operators. I will give reasons for pursuing
the latter course, and results using this extended effective theory for
calculating the higgs' pt spectrum. - Host: F. Petriello
- Physics Department Colloquium
- Gamma Ray Bursts and the Birth of Black Holes
- Time: 4:00 pm
- Place: 2241 Chamberlin Hall (coffee and cookies at 3:30 pm)
- Speaker: Neil Gehrels, NASA Greenbelt, U-Maryland, Penn State U
- Abstract: Black holes have been predicted since the 1940's from solutions of Einstein's general relativity field equation. There is strong evidence of their existence from astronomical observations, but their origin has remained an open question of great interest. Gamma-ray bursts may the clue. They are powerful explosions, visible to high redshift, and appear to be the birth cries of black holes. The Swift and Fermi missions are two powerful NASA observatories currently in orbit that are discovering how gamma-ray bursts work. Evidence is building that the long and short duration subcategories of GRBs have very different origins: massive star core collapse to a black hole for long bursts and binary neutron star coalescence to a black hole for short bursts. The similarity to Type II and Ia supernovae originating from young and old stellar progenitors is striking. Bursts are tremendously luminous and are providing a new tool to study the high redshift universe. One Swift burst at z=8.3 is the most distant object known in the universe. The talk will present the latest gamma-ray burst results from Swift and Fermi and will highlight what they are teaching us about black holes and jet outflows.
- Host: Ogelman