Colloquium
Junior and senior physics majors attend our biweekly colloquium series, held on Tuesday afternoons at 4:30 pm in Shanahan B460. The talks are open to all students and to the public, and are frequently attended by scientists from the other Claremont Colleges, Cal Poly Pomona, and others. The series features speakers from a broad range of institutions and fields of physics.
| March 7, 2006 | John Clarke, University of California at Berkeley The Ubiquitous SQUID: From Cosmology to Medicine |
Many materials become superconducting at sufficiently low temperatures. In the superconducting state, electrons of opposite momentum and spin form Cooper pairs. These pairs constitute a single, macroscopic quantum state that is described by a quantum mechanical wave function with well defined amplitude and phase. This quantum state is responsible for the zero-electrical resistance of superconductors and for such properties as ... | |
| Feb. 21, 2006 | Michael Wood-Vasey (’98), Harvard University The Accelerating Universe and You: The Past, Present, and Future of Exploring the Universe With Supernovae |
The field of cosmology has been revolutionized in the last decade by the discovery that the expansion of the Universe is accelerating. This remarkable conclusion was first derived by using Type Ia supernovae as standardizable cosmological candles. Since this initial work, a number of complementary cosmological measurements have led to our current "concordance" cosmological model that states that 70% of ... | |
| Jan. 31, 2006 | Theresa Lynn, Caltech Ultra-High Energy Cosmic Rays: The Mystery of Nature’s Most Powerful Particle Accelerators |
Stargazing is perhaps one of humanity’s oldest pastimes. As modern astronomers have learned to image the universe in wavelengths across the electromagnetic spectrum, each added picture has answered old questions and uncovered new wonders. In recent years a few observatories have concentrated on very different messengers from the cosmos: subatomic particles called cosmic rays which reach us from as nearby ... |
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| Jan. 24, 2006 | Martin Madsen, University of Michigan Experimental Quantum Mechanics: Exploring the Quantum World One Atom at a Time |
"Atoms on a small scale behave like nothing on a large scale, for they satisfy the laws of quantum mechanics," observed Richard Feynman, one of the most brilliant physicists of the 20th century. We can now explore the unusual behavior of a single atom through the combination of an electrical trap and lasers that enable us to isolate and control ... | |
| Jan. 17, 2006 | Erik Helgren, University of California at Berkeley Optical Properties of Disordered Systems: Terahertz Spectroscopy of Doped Silicon |
The terahertz (THz) spectral range has been under-utilized in the past both in fundamental research as well as in commercial applications. This spectral range is extremely important for studying condensed matter systems because the photon energy associated with THz frequencies is sub-meV, a typical energy for correlated electron physics; for instance this energy corresponds to the Cooper pair binding energy ... | |
| Nov. 28, 2005 | Douglas Osheroff, Stanford University The Discovery of Superfluid :mil:`\mathrm{He}^3` as Seen Through the Eyes of a Graduate Student |
It was at the beginning of his fifth year of graduate study that Douglas Osheroff discovered evidence for the existence of two unexpected phase transitions in a mixture of liquid and solid He3, both within three thousandths of a degree of absolute zero. The speaker will describe this event, and give his personal account of the excitement and confusion that ... | |
| Nov. 15, 2005 | David Awschalom, University of California at Santa Barbara Spintronics, Semiconductors, Molecules, and Quantum Information Processing |
There is a growing interest in exploiting electronic and nuclear spins in semiconductor nanostructures for the manipulation and storage of information in emergent technologies based upon spintronics and quantum logic. Such schemes offer qualitatively new scientific and technological opportunities by combining elements of standard electronics with spin-dependent interactions between electrons, nuclei, electric and magnetic fields. Here we provide an overview ... | |
| Nov. 8, 2005 | Nathan Lewis, Caltech Scientific Challenges in Sustainable Energy Technology |
This presentation will describe and evaluate the challenges, both technical, political, and economic, involved with widespread adoption of renewable energy technologies.
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| Oct. 25, 2005 | Mark Beck, Whitman College Interference, Complementarity, Entanglement and All That Jazz |
Technology has advanced to the point where it is possible for undergraduates to perform experiments exploring fundamental aspects of quantum mechanics--experiments observing behavior such as wave-particle duality, entanglement, and nonlocality. At Whitman College we are developing a series of such undergraduate laboratories, and I will describe some of these. In one we perform an interference experiment with single photons where ... | |
| Oct. 11, 2005 | Gabriela Canalizo, University of California at Riverside Galaxy Collisions and the Birth of Quasars |
Quasars are some of the most powerful objects in the Universe, and their study allows us to probe the early Universe. However, there are still many uncertainties regarding their nature and, in particular, the way in which they are formed. In this talk, I review the role of supermassive black holes, starbursts, and galaxy collisions in the life of quasars. | |
| Sept. 27, 2005 | Thomas D. Donnelly, Harvey Mudd College Production and Application of an Aerosol of Micron-Scale Particles |
A device that uses ultrasonic atomization of a liquid to produce an aerosol of micron-scale droplets will be discussed. This device represents a new approach to producing targets relevant to laser-driven fusion studies, and to the relatively untested subfield of nonlinear optics in which wavelength-scale targets are irradiated. The device has also made possible tests of fluid dynamics models in ... | |
| Sept. 13, 2005 | Kerry Vahala, Caltech :mil:`Q` > Million Optical Microresonators on Silicon Chips |
A novel laser processing method has been applied to create optical micro-resonators having Q factors as high as 500 million on silicon wafers. The combination of Ultra-high-Q and small mode volume opens up new applications for wafer based resonators. In this talk I will first review the processing and passive optical properties of these devices and then describe their application ... | |
| Sept. 6, 2005 | HMC juniors and seniors, Harvey Mudd College What I Did on My Summer Vacation: Off-Campus Summer Research Experiences |
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| April 26, 2005 | Mark Vagins, University of California at Irvine Close Encounters of the Absurd Kind — A Scientist Looks at UFO’s |
Look! Up in the sky! It’s a bird? It’s a plane? It’s... a weather balloon? What’s the real deal with America’s ongoing UFO obsession, anyway? What does a professional astrophysicist with an interest in the offbeat think about the whole paranormal scene? Come on an exploration of the claims and issues involved, both from a scientific perspective and through the ... | |
| April 19, 2005 | Jerry Gollub, Haverford College Chaotic Dynamics of Mixing in Fluids |
The process by which an impurity is dispersed in a stirred fluid is important for many areas of science and engineering. It can occur as a consequence of turbulence (e.g. in stirring coffee), but mixing also occurs even in some laminar flows that cause nearby fluid elements to separate exponentially in time. This process is sometimes called "chaotic mixing". Until ... |
