Dr. Geoff Greene University of Tennessee, Knoxville While neutrons within nuclei may be stable, the free neutron is unstable against beta decay and has a mean lifetime of ~15min. Free neutron beta decay is, perhaps, the simplest weak nuclear process as it is uncomplicated by many body effects that are present in the decay of nuclei. As a result, it can be directly understood in terms of rather simple fundamental weak interaction theory. Additionally, because free neutron decay is the "prototype" for all nuclear beta decays, the neutron lifetime is a fundamental parameter whose value is important not only in nuclear physics, but also in astrophysics, cosmology, and particle physics. I will give an introduction to the theory of weak nuclear decay and briefly discuss the importance of the neutron lifetime as a parameter in the Big Bang. A review of the experimental strategies for the measurement of the neutron lifetime will be given as well as a discussion of the puzzling discrepancy among the measurements with the lowest quoted uncertainty. Finally, I present a very new result recently obtained at the NIST Cold Neutron Research Facility in Gaithersburg Md.
Professor Emeritus, U Kentucky. He is the winner of the 1978 Herskovits Prize for his history of Nubia, Nubia: Corridor to Africa. In 2005 Adams was awarded the Order of the Two Niles, Sudan's highest civilian honor, for his contributions to Nubian history. Adams's work in Nubia began in 1959 as part of the UNESCO archaeological salvage campaign to excavate sites threatened by the rising flood waters of Lake Nasser following the construction of the Aswan Dam.
Recently there have been significant theoretical and experimental efforts to understand and identify the so-called topological phases of matter in interacting electron systems. These topological phases may be characterized by different kinds of topological properties such as non-trivial edge/surface states and/or unusual elementary excitations in the bulk or surface. Notable examples include quantum spin liquids, topological insulators, and other closely related phases. One of the main challenges is to come up with theoretical criteria that can be used to identify or predict correlated materials that hold promise for the emergence of such topological phases. We discuss recent theoretical and experimental developments in this direction, along with a brief introduction to some of the proposed topological phases. In particular, we focus on correlated materials with strong spin-orbit coupling and/or near a metal-insulator transition.
I am originally from Greensburg, Kentucky, but have lived in Lexington since 2000. My undergraduate degree is in English, with a minor in computer science, and I also have a J.D. from the UK College of Law. I have been working for A&S for three years.
1. What do you do in your spare time? Usually, anything that gets away from the internet/email/etc. I enjoy going to see live music when I can, even when I¹ve never heard of the band. I also like to get out and run or walk my dog, especially when the weather cooperates.
2. What is your favorite movie or book? I don't know that I have a favorite, but I really enjoy utopian/dystopian literature. Even books I would consider fairly terrible tend to be humorous or interesting, while the better works have themes so deep that I get something new with each read.