Seminar Thursday Aug 21 – Lindsay Goodwin

Speaker: Lindsay Goodwin
Location: Physics 175
Time: 3:30, August 21 2014

Abstract: Multi-point in situ measurements from the Swarm spacecraft in a string-of-pearls configuration provide a novel tool to investigate the creation, transport, and evolution of polar cap patches. Swarm observes a sequence of density features being created and structured in the northern Scandinavian dayside cusp by particle impact ionization. These features become entrained in the polar-cap convection pattern, and evolve into lower-density polar cap patches. Equatorward, a long-lived and robust westward flow channel is seen eroding dayside plasma. This channel prevents the dayside solar-ionized plasma from directly entering the cusp precipitation region, but possibly allows for the creation of higher-density plasma further in the polar cap. These are the first observations of a series of patches entrained in the polar cap flow, on the way from their source (the cusp) to the nightside auroral oval.

Seminar Thursday Aug 14 – Stephanie Goertzen

Speaker: Stephanie Goertzen
Location: Physics 175
Time: 3:30, August 14 2014

Abstract: Recently, the discovery of a new class of materials called topological insulators has stimulated much excitement in the field of condensed matter physics. Their discovery has also begun the search for the exotic topological superconductor – a superconductor whose properties are protected by topology. A novel feature of such topological superconductors is the possible existence of the Majorana fermion as an elementary excitation. Traditionally, the Hamiltonian of the system is directly diagonalized in order to calculate the mean-field potentials. However this method is very computationally expensive and is widely regarded as impractical. As such, we make use of two efficient numerical algorithms that have recently been developed in order to self-consistently solve the Bogoliubov-de Gennes equations. The first is Chebyshev polynomial expansion which allows us to bypass directly diagonalizing the Hamiltonian and the second is the Sakurai-Sugiura (SS) method for efficient computation of eigenvalues and eigenvectors. Armed with this combination of techniques, we aim to investigate two-dimensional topological superconductivity.

Seminar Thursday Aug 07 – Jason Ho

Speaker: Jason Ho
Location: Physics 175
Time: 3:30pm, August 07 2014

Title: QCD sum-rules analysis of open-charm hybrid mesons

Abstract: We briefly discuss the development of quantum chromodynamics (QCD) and introduce the concept of hadronic structures outside the quark model. Within this group of unconventional hadrons, of interest to us are hybrid mesons consisting of a quark-antiquark pair and a constituent gluon.
Through the use of QCD sum-rules, we intend to calculate the ground state mass of the D (charm quantum number c = \pm 1) and D_s (charm/strange quantum numbers c = s = \pm 1 ) hybrid mesons with exotic J^{PC} = 1^{-+} (spin J, parity P, and charge conjugation C), and present preliminary results.