Theory Talk is an informal setting for fellow NC State physicists to see and hear work currently being pursued within the department. Speakers are encouraged to talk about work in progress and exchange ideas with the audience. Faculty, postdocs, and especially graduate students are encouraged to attend and present. Interested visitors and researchers from the Triangle area are also welcome.

FALL 2009 SCHEDULE

Zhiping Yin (UC Davis)
The iron pnictide superconductors: a DFT perspective
Fri., Oct. 2, 3:00-4:00, Riddick 400P Conference Room

Liliana Caballero
Accretion Disks: Neutrino Emission
Wed., Oct. 7, 3:00-4:00, Riddick 400P Conference Room

Thomas Schaefer
Density Functional Theory for Cold Fermi Gases at Infinite Scattering Length
Fri., Oct. 23, 3:00-4:00, Riddick 400P Conference Room

I will discuss an energy density functional for cold atomic gases at ``unitarity'', which is the limit in which the two body scattering length is infinite but the effective range is small compared to the inter-particle distance. These systems can be studied in the laboratory (using atomic traps), on the computer, and in the heavens (using neutron stars).

Michael Buchoff (Univ. of Maryland)
Extracting Scattering Parameters using the Isospin Chemical Potential
Thurs., Nov. 5, 4:00-5:00, Riddick 400P Conference Room

Hadronic scattering mediated through the strong interaction has been an area of great interest for both theory and experiment. Recently, lattice QCD calculations of scattering processes from first principles have seen remarkable progress, including multiple calculations of two-pion scattering lengths that agree with experiment to within a few percent. However, there exists a certain class of scattering processes, such as pion-nucleon scattering, that contain annihilation diagrams, which are prohibitively expensive to simulate on the lattice. In this talk, I will present a method to extract certain parameters from this class of scattering processes by employing an isospin chemical potential, which can be simulated on the lattice as a result of its positive-definite fermion determinant.

Matt Braby
Transport Properties for Strongly-Coupled Systems: Cold Atoms, Color Superconductors, and the Quark-Gluon Plasma
Fri., Nov. 13, 3:00-4:00, Riddick 400P Conference Room

Chueng-Ryong Ji
Significance of Lepton Current in Deeply Virtual Compton Scattering
Fri., Nov. 20, 3:00-4:00, Riddick 400P Conference Room

Issue of extracting the generalized parton distribution (GPD) from the deeply virtual Compton scattering (DVCS) has been widely discussed in recent literatures of hadron physics. I'll discuss this issue and pay more attention to the lepton current in DVCS. It reveals treacherous points in obtaining the agreement between the full calculation of DVCS and the reduced calculation using the GPD formulation.