We are working on scheduling Physics Faculty Seminars for Spring 2015. Please check again soon for updates.
Past Physics Faculty Seminars
Friday, April 5, 2013 -- Professor Gerald Guralnik
"Heretical Ideas that led to the Search for the Higgs Boson"
I will discuss the state of particle physics in the 1960's and the path that led to my paper with Hagen and Kibble predicting what is now known as the Higgs Boson. I will describe the basic problems that made the results of this paper surprising. I will also address some of the technical issues which have recently been raised in conference talks and physics blogs.
Friday, February 22, 2013 - Professor Herb Fried
"A New, Analytic, Non-Perturbative, Gauge-Invariant Formulation of Realistic QCD"
Some five decades ago, Functional Quantum Field Theory (FQFT) was formulated, principally by Schwinger, Symanzik, and Fradkin, as a formalism - quite independent of Feynman graphs - for calculating the probability amplitudes for any physical process of any causal QFT. A few decades later, when the Quarks and Gluons of QCD came upon the scene, the emphasis was on attempting to employ perturbative Feynman graphs, or summing sub-sets of such graphs presumably needed for these strong-coupling processes. But the direct summation of ALL higher-order perturbative graphs, in any theory, is physically and mentally impossible; and in QCD even attempting to calculate the sum of the first few orders became horrendous. Other non-perturbative attempts were made, using Bethe-Salpeter equations, or the Renormalization Group, but the results still contain a perturbative component, and in that sense are not satisfactory.
What to do? Return to the original Functional Formulation, and notice how two, overlooked possibilities - which should have been seen a half-century ago - and which, when combined, lead to a formulation of QCD expressed in the title of this Presentation, allow one to calculate - using pencil and paper - quark-binding potentials, and the simplest nucleon-nucleon potential (as in forming a deuteron), with obvious generalizations to heavier nuclei. All gluon exchanges between quarks are summed, and the results are explicitly and exactly gauge invariant. Using these functional techniques, many long-standing problem in and of QCD can be re-examined in this new formulation, which turns out to be surprisingly simple and efficient.