ColloquiaAll colloquia are held in the Cunniff lecture hall, which is room 199 of the Science Center. Friday colloquia begin at 12:45 p.m. (unless otherwise noted). Pizza and drinks are served at 12:20 p.m. just outside the hall. There are also pre-colloquium talks for some of our visitors' colloquia. These are given by faculty members, usually a week before the actual colloquium, and are a good way for students (and others) to get background information to help them better understand the colloquium. For questions regarding the speakers and topics, please contact Prof. Catherine Crouch (ccrouch1 at swarthmore dot edu) at (610) 328-8386. Useful links
String Theory, The Final Frontier?Vatche Sahakian, Department of Physics, Harvey Mudd CollegeFri, Sep. 18, 2009, 12:45 PM Since the 1970’s, we’ve known of a major inconsistency in the laws of modern physics: quantum mechanics is seemingly incompatible with gravitational physics…String theory purports to be the leading framework to address and resolve this issue. But, does it really succeed, or is it simply a clever scheme to keep theoretical physicists like me employed? We will explore this question by looking at exotic phenomena involving black holes and implications from the cosmic microwave background radiation. More information is available at Prof. Sahakian's website. Loopy Stabilization of RNA Loops: How Entropy Creates OrderDaniel Aalberts, Department of Physics, Williams CollegeFri., Oct. 30, 2009, 12:45 PM Predicting nucleic acid folds has been a topic of intense investigation because structure implies function and as an analog to the protein folding problem. We show, surprisingly, that loop entropy actually promotes tertiary order. By including this overlooked source of stabilization, we improve the accuracy in predicting tRNA and other folds. More information is available at Prof. Aalberts's website. Pre-colloquium talk by Catherine Crouch on Friday, Oct. 23, 2009, 12:45 in Cunniff All Things Pyramids: A New Nanostructure for Diagnostics and TherapeuticsTeri W. Odom, Chemistry and Materials Science & Engineering, Northwestern UniversityThu., Nov. 19, 2009, 4:30 PM (Note date and time) Plasmonics is an exciting and emerging area that uses metal nanostructures to manipulate light on the nanoscale. Depending on their size, shape, and materials properties, noble metal nanoparticles can scatter and absorb light to produce colors ranging from the ultra-violet to the near-infrared. The physical basis behind these interesting properties is the interaction between surface conduction electrons and light; these collective excitations are surface plasmons (SPs). In general, there are two types of SPs: localized surface plasmons (LSPs) and surface plasmon polaritons (SPPs). This talk will focus on the optical properties of two different but complementary systems that can control light on the nanometer scale: (i) nanofabricated pyramidal particles and (ii) nanopyramidal plasmonic crystals. Both types of nanostructures can be fabricated by our large-area, nanoscale patterning tools. For the nanoparticle case, pyramids can be generated with variable sizes, thicknesses, and multi-material compositions and designed with blunt, ultra-sharp, or even without tips. Applications of the LSPs of these particles include bioimaging and localized cancer therapeutics. For the plasmonic crystal case, these artificially structured materials exhibit band structure analogous to crystalline solids. The SPPs generated by these lattices can be used for real-time, label-free sensing of biomolecules and other proteins. More information is available at Prof. Odom's website. As are two relevant papers of Dr. Odom's: "Screening plasmonic materials using pyramidal gratings" and "Pyramids: a platform for designing multifunctional plasmonic particles."
Pre-colloquium talk by Catherine Crouch on Friday, Nov. 13, 2009, 12:45 in SC 128 Chromic Liquid Crystals: Molecular Aggregation in an Extremely Strong Magnetic FieldPeter Collings, Department of Physics, Swarthmore CollegeFri., Dec. 4, 2009, 12:45 PM TBA More information is available at Prof. Collings's website.
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