54,819 research outputs found
A simplified test of universality in Lattice QCD
A simplified test of universality in Lattice QCD is performed by analytically
evaluating the continuous Euclidean time limits of various lattice fermion
determinants, both with and without a Wilson term to lift the fermion doubling
on the Euclidean time axis, and comparing them with each other and with the
zeta-regularised fermion determinant in the continuous time--lattice space
setting. The determinant relations expected from universality considerations
are found to be violated by a certain gauge field-dependent factor, i.e. we
uncover a "universality anomaly". The physical significance, or lack thereof,
of this factor is a delicate question which remains to be settled.Comment: 6 pages. v2: Revised to include a further result on the
zeta-regularised fermion determinant in the continuous time--lattice space
setting which impacts on the conclusions; typos corrected; acknowledgement
and reference added; to appear in Phys.Rev.Let
Remote Stratigraphic Analysis: Combined TM and AIS Results in the Wind River/bighorn Basin Area, Wyoming
An in-progress study demonstrates the utility of airborne imaging spectrometer (AIS) data for unraveling the stratigraphic evolution of a North American, western interior foreland basin. AIS data are used to determine the stratigraphic distribution of mineralogical facies that are diagnostic of specific depositional environments. After wavelength and amplitude calibration using natural ground targets with known spectral characteristics, AIS data identify calcite, dolomite, gypsum and montmorillonite-bearing strata in the Permian-Cretaceous sequence. Combined AIS and TM results illustrate the feasibility of spectral stratigraphy, remote analysis of stratigraphic sequences
Synthesis, solution stability, and crystal structure of aza-thia macrocyclic complexes of silver(I).
The evaluation of partial binocular overlap on car maneuverability: A pilot study
An engineering approach to enlarge the helmet mounted display (HMD) field of view (FOV) and maintain resolution and weight by partially overlapping the binocular FOV has received renewed interest among human factors scientists. It is evident, based on the brief literature review, that any panoramic display with a binocular overlap, less than a minimum amount, annoys the viewer, degrades performance, and elicits undesirable behavior. The major finding is that across the 60 deg conditions, subjects moved their heads a greater distance (by about 5 degs on each side) than in the 180 deg condition, presumably to compensate for the lack of FOV. It is quite clear that the study, based on simple car maneuverability and two subjects, reveals differences in FOV, but nothing significant between binocular overlap levels and configurations. This tentatively indicates that some tradeoffs of binocular vision for a larger overall display FOV are acceptable
General bounds on the Wilson-Dirac operator
Lower bounds on the magnitude of the spectrum of the Hermitian Wilson-Dirac
operator H(m) have previously been derived for 0<m<2 when the lattice gauge
field satisfies a certain smoothness condition. In this paper lower bounds are
derived for 2p-2<m<2p for general p=1,2,...,d where d is the spacetime
dimension. The bounds can alternatively be viewed as localisation bounds on the
real spectrum of the usual Wilson-Dirac operator. They are needed for the
rigorous evaluation of the classical continuum limit of the axial anomaly and
index of the overlap Dirac operator at general values of m, and provide
information on the topological phase structure of overlap fermions. They are
also useful for understanding the instanton size-dependence of the real
spectrum of the Wilson-Dirac operator in an instanton background.Comment: 26 pages, 2 figures. v3: Completely rewritten with new material and
new title; to appear in Phys.Rev.
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