A Gettysburg Streetscape, North Washington Street in 1925

This paper explores life in Gettysburg on North Washington Street in 1925. It was the final project for Dr. Michael Birkner\u27s Spring 2017 Historical Methods class

Effective Monopole Potential for SU(2) Lattice Gluodynamics in Spatial Maximal Abelian Gauge

We investigate the dual superconductor hypothesis in finite-temperature SU(2) lattice gluodynamics in the Spatial Maximal Abelian gauge. This gauge is more physical than the ordinary Maximal Abelian gauge due to absence of non-localities in temporal direction. We show numerically that in the Spatial Maximal Abelian gauge the probability distribution of the abelian monopole field is consistent with the dual superconductor mechanism of confinement: the abelian condensate vanishes in the deconfinement phase and is not zero in the confinement phase.Comment: LaTeX2e, 8 pages with 3 EPS figures, uses epsf.st

Perturbative Expansion around the Gaussian Effective Action: The Background Field Method

We develop a systematic method of the perturbative expansion around the Gaussian effective action based on the background field method. We show, by applying the method to the quantum mechanical anharmonic oscillator problem, that even the first non-trivial correction terms greatly improve the Gaussian approximation.Comment: 16 pages, 3 eps figures, uses RevTeX and epsf. Errors in Table 1 are corrected and new references are adde

Negative-Energy Spinors and the Fock Space of Lattice Fermions at Finite Chemical Potential

Recently it was suggested that the problem of species doubling with Kogut-Susskind lattice fermions entails, at finite chemical potential, a confusion of particles with antiparticles. What happens instead is that the familiar correspondence of positive-energy spinors to particles, and of negative-energy spinors to antiparticles, ceases to hold for the Kogut-Susskind time derivative. To show this we highlight the role of the spinorial ``energy'' in the Osterwalder-Schrader reconstruction of the Fock space of non-interacting lattice fermions at zero temperature and nonzero chemical potential. We consider Kogut-Susskind fermions and, for comparison, fermions with an asymmetric one-step time derivative.Comment: 14p

Disentangling Electron-Boson Interactions on the Surface of a Familiar Ferromagnet

We report energy renormalizations from electron-phonon and electron-magnon interactions in spin minority surface resonances on Ni(111). The different interactions are disentangled and quantified in strength $\lambda$, based on the characteristic shapes of their complex self-energies, and the largely different binding energies at which they occur. The observed electron-magnon interactions reveal a strong dependence on momentum and energy band position in the bulk Brillouin zone. In contrast, electron-phonon interactions from the same bands are observed to be practically momentum- and symmetry-independent. Additionally, a moderately strong ($\lambda>0.5$) electron-phonon interaction is observed from a `buried', near-parabolic spin majority band that does not cross the Fermi level.Comment: QuSpin 202