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.
HMC Physics Colloquium shot
March 27, 2012 Jeanie Lau, University of California at Riverside
One, Two, Three — Quantum Transport Suspended Graphene Devices
Graphene, a two-dimensional single atomic layer of carbon, has recently emerged as a promising candidate for electronic materials, as well as a new model system for condensed matter physics. In this talk I will present our work on mechanical, thermal, and electrical properties of suspended graphene devices, such as ripple texturing, negative thermal expansion, spontaneous symmetry breaking and gap formation ...
March 6, 2012 John M. Martinis, University of California at Santa Barbara
Design of a Superconducting Quantum Computer
The computational power of a quantum computer arises from the superposition of quantum states, which gives a net parallel-processing size that exceeds the number of atoms in the universe for even a modest 300-qubit processor. To build such a computer, many groups around the world are exploring whether experimental systems can be controlled sufficiently well and with enough quantum coherence. ...
Feb. 21, 2012 Ann Esin, Richard Haskell, and Richard Mawhorter, Harvey Mudd College
Recent Developments in Physics
Measuring the universe using black holes (Esin); Biological-cell lasers: novelty or useful tool (Haskell); Electrons remaining stubbornly spherical (Mawhorter).
Feb. 7, 2012 Charlie Doret, Georgia Tech Research Institute
Milking Superposition: Processing Information Using the Quantum States of Trapped Calcium Ions
Two-state quantum systems may be used for encoding information in ways analogous to the bits of a conventional computer. Unlike discrete classical bits, however, quantum bits (qubits) may occupy superposition states in which they are simultaneously both 0 and 1. By manipulating such qubits it is possible to store and process information in new and powerful ways. Computation utilizing these ...
Jan. 24, 2012 David Hoogerheide, Harvard University
Solid State Nanopores as Nanoscale Detectors: Single Molecules, Fast Kinetics, and Ionic Liquids
The advent of nanotechnology has created new possibilities for understanding the world and developing technologies to shape it. Nanoscale devices are useful for studying the behavior of very small numbers of molecules; because of their small size, however, nanodevices are particularly sensitive to fluctuations. One such device is the solid state nanopore, which is a promising platform for next-generation DNA ...
Jan. 17, 2012 Daniel Wagenaar, Caltech
Multisensory Integration in an Invertebrate Predator
Obtaining information from the environment to guide behavior is one of the most fundamental functions of nervous systems. Since individual cues are rarely 100% reliable, many animals (including humans) combine cues across sensory modalities to improve the quality of their decisions and make their behavior more robust under variable circumstances. In mammals, this "multisensory integration" involves many billions of neurons ...
Nov. 22, 2011 Peter N. Saeta, Harvey Mudd College
Enhancing Light Absorption in Solar Cells
Photovoltaics are the fastest-growing renewable energy source over the last three years and have the potential to supply a significant fraction of our electricity needs. Conventional silicon cells are made of thick crystals because silicon is a weak absorber in the infrared and much of the visible. Thin solar cells require less energy and material to make and may lead ...
Nov. 8, 2011 E. Sterl Phinney, Caltech
Mergers and Liquidations Among White Dwarf and Neutron Star Binaries
This year’s Nobel prize in physics was given for using Type Ia supernovae as standard candles to discover that dark energy now dominates the dynamics of the universe. Disconcertingly, recent research has uncovered problems with both of the two popular models for Type Ia supernovae. One is in trouble with observational data, and the other with careful theoretical calculations, which ...
Oct. 25, 2011 A. J. Shaka (’80), University of California at Irvine
Deep Green: Long-Term Zero-Carbon Power for the 21st Century
It is becoming more and more obvious that continued burning of fossil fuels, with the large influx of carbon dioxide into the atmosphere, could prove to be an enormous and expensive future problem. Furthermore, even if such changes could be weathered, the fossil fuels themselves will be exhausted, become expensive, and require more and more destructive methods to extract. For ...
Oct. 4, 2011 Bruce McCandless II, NASA
Life in Interesting Times
Captain McCandless, the first person to perform an untethered spacewalk, will review the current status of our human spaceflight program — with its uncertainties, ongoing activities, opportunities, and long-term goals. He will also present a scholarship from the Astronaut Scholarship Foundation to Paul Riggins ’12. Riggins is one of only 26 students nationwide this year to receive the prestigious award.
Sept. 20, 2011 Eric Fullerton (’84), University of California at San Diego
Exploiting the Spin Angular Momentum to Control Magnetism at the Nanoscale
In most magnetic applications the orientations of the magnetic elements are controlled by external magnetic fields. However, it has recently been appreciated that the relative orientations of nano-magnets can be controlled directly by the injection of spin-polarized currents known as spin-transfer effects. This results fundamentally from the transfer of angular momentum from the spin current to the magnetic material. While ...
Sept. 6, 2011 Eleven HMC Physics Majors, Harvey Mudd College
Summer 2011 Off-Campus Research
Lucas Brady, Cameron Conti, Jake Fish, Chris Gage, Robert Hoyt, Erik Littleton, Laura Maguire, Shaun Pacheco, Carola Purser, Brad Perfect, Wylie Rosenthal, and Ryan Waldman will briefly describe their summer research experiences.
April 19, 2011 Persis S. Drell, SLAC
The Turn On of LCLS: The X-Ray Free-Electron Laser at SLAC
On April 10, 2009, the world’s first hard X-ray free-electron laser was brought to lasing. Producing an X-ray beam with more than a billion times higher peak brightness than the most powerful existing synchrotron sources, it marked the beginning of a new era of science. Since October 2009, users have been performing experiments at the SLAC Linac Coherent Light Source ...
March 29, 2011 Alice Shapley, University of California at Los Angeles
The Contribution of Galaxies to the Reionization of the Universe
There are critical outstanding questions about the formation of galaxies, and their impact on the intergalactic medium (IGM). One important goal is to determine the origin of the ultraviolet radiation field that reionized the universe and maintained the ionization of the IGM. This question becomes more pressing as we discover ever more distant galaxies, probing back to the earliest epochs ...
March 8, 2011 Gerard C. L. Wong, University of California at Los Angeles
Condensed Matter Physics and Bacteria
One of the unsolved problems in human health and disease is the control of pathogens, such as antibiotic-resistant forms of bacteria. In this talk, we will briefly describe three vignettes where physics-based approaches have been useful.

  1. Bacterial biofilms are structured multi-cellular communities that are notoriously resistant to antibiotics. By adapting algorithms from colloid physics, we translate bacteria movies ...