## 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.
 April 9, 2013 Nathaniel Gabor, Massachusetts Institute of Technology Atomically Thin Photodetectors: the Ideal Semi-Metal vs. the Insurmountable Insulator Graphene, an atomically thin sheet of hexagonally oriented carbon, is a zero-band-gap conductor (semi-metal) that exhibits extraordinary electronic behavior and broadband optical absorption. Hexagonal boron nitride, which shares a similar structure to that of graphene, is a highly insulating electronic material that does not absorb any light in the visible spectrum. By combining graphene and boron nitride into ultrathin vertical ... March 26, 2013 Robert Treuhaft, Jet Propulsion Laboratory The Physics in the Forest: Remote Sensing of Tropical Forests with Interferometric SAR and Lidar When trees are cut down, they release their carbon to the atmosphere in $$\mathrm{CO}_2$$. After fossil fuels, deforestation is the second largest anthropogenic contributor to atmospheric $$\mathrm{CO}_2$$. Tropical forests contain about 50% of Earth’s forested biomass, and they account for most deforestation. The degree to which a forest is storing carbon or releasing it to the atmosphere ... March 12, 2013 Frederick H. Streitz ’83, P’13, Lawrence Livermore National Laboratory Opening Frontiers with Extreme Capability Computing Lawrence Livermore has a long history of fielding some of the world’s largest computers, fueled by our nearly insatiable need for both capacity and capability computing. Each new generation in computing brings with it the ability to perform simulations that were impossible with the earlier computers. I will discuss the development of three applications designed to run on the largest ... March 5, 2013 David Weld, University of California at Santa Barbara Cold Atom Quantum Simulation Ultracold neutral atoms trapped in optical lattices represent a new frontier for the investigation of outstanding problems in many-body quantum mechanics. These systems promise to bring the precision and control of atomic physics to bear on important problems in condensed matter physics, from nonequilibrium spin dynamics to d-wave superconductivity. The ambit of this fast-growing field is expanding from measurement to ... Feb. 19, 2013 Jing Xu, University of California at Merced Molecular Motor Biophysics: Hardware Instrumentation and Nonlinear Physics Experimental biophysicists build instruments to study nature’s nano-machines. Molecular motors are nano-machines and are crucial for life: they transport materials in cells. Motor-based transport is inherently a many body problem, and exhibits complex behavior yet to be understood. An analytic model for multiple motor transport has been proposed, but has remained untested. In this talk, I will discuss the construction ... Feb. 5, 2013 Nima Dinyari, University of Oregon Pursuing a Cavity QED System that Couples a Nitrogen Vacancy Center to a Whispering Gallery Mode Silica Microresonator Cavity quantum electrodynamics (QED) provides a model system for studying the controlled, coherent coupling of optical and atomic quantum bits. Our research is focused on developing a cavity QED system that couples a nitrogen vacancy (NV) center in a diamond nanostructure to a whispering gallery microresonator. We have developed a composite system that allows for a diamond nanopillar to be ... Jan. 22, 2013 Itai Cohen, Cornell University Flight of the Fruit Fly There comes a time in each of our lives where we grab a thick section of the morning paper, roll it up and set off to do battle with one of nature’s most accomplished aviators — the fly. If however, instead of swatting we could magnify our view and experience the world in slow motion we would be privy to ... Dec. 4, 2012 Tom Donnelly, Harvey Mudd College Using High-Power, Pulsed Lasers to Generate Hot, Dense Environments: A Fusion Testbed When they where first invented in 1960, someone quipped that “Lasers are a solution waiting for a problem.” That challenge has been met so effectively that today lasers are ubiquitous in everyday life, to say nothing of their presence in laboratories. A series of scientific, engineering, and material-science breakthroughs have allowed lasers to become ever more powerful, and today laser ... Nov. 13, 2012 Briony Horgan, Arizona State University Good Vibrations for Habitable Environments on Ancient Mars from Orbital Spectroscopy Infrared spectroscopy from NASA satellites around Mars has revolutionized our understanding of what the surface of the planet looked like 4 billion years ago. In this talk, I will discuss the physics behind solid-state vibrational spectroscopy of minerals at these wavelengths, how we interpret signals from a planetary surface, and how we can use mineralogical data to infer climatic and ... Oct. 30, 2012 Slobodan Mitrovic, Caltech Thermoelastic Phononic Metamaterials An independent control over electrical and thermal properties is one of the central goals in the search for efficient thermoelectric materials for waste heat energy conversion. A good thermoelectric will have high electrical, but low thermal conductivity. Nature, however, does not seem to favor this dissociation, and the best synthesized thermoelectrics in use today remain at about the same efficiency ... Oct. 16, 2012 Keith Schwab, Caltech Quantum Mechanics with Mechanical Structures There appears to be no fundamental reason why macroscopic mechanical objects cannot demonstrate quantum phenomena such as energy quantization, superposition states, and entanglement. In fact, in recent years, researchers have been successful in demonstrating a few of these basic states in the laboratory including the quantum ground state of motion and the exchange of a single quantum with a superconducting ... Oct. 2, 2012 John S. Townsend, Harvey Mudd College Why the Higgs Boson is Called “The God Particle” I will discuss how spontaneous symmetry breaking in gauge theories via the Higgs mechanism generates the masses of the elementary particles. Sept. 25, 2012 Philip Muirhead, Caltech Small Stars with Small Planets and Big Consequences With the success of NASA’s Kepler Spacecraft, extrasolar planet science has entered a new era. Prior to Kepler’s launch exoplanet science was primarily concerned with gas-giant exoplanets, since gas giants comprised the majority of discoveries, numbering in the hundreds. NASA’s Kepler Mission has since discovered thousands of exoplanets with many of them terrestrial-sized. Of particular interest are terrestrial exoplanets orbiting ... Sept. 11, 2012 Nate Bean, Chris Cotner, Jake Fish, Robert Kealhofer, Erik Littleton, Laura Maguire, Luke Mastalli-Kelly, Bradley Perfect, Carola Purser, and Michelle Vick, Harvey Mudd College What I did for summer research Several HMC physics majors discuss how they landed summer research positions and what they did. April 17, 2012 Peter Goldreich, Caltech Physics in Everyday Life Examples will be drawn from human metabolism, sports, flight, and weather.