3,668 research outputs found
Representations of reductive normal algebraic monoids
The rational representation theory of a reductive normal algebraic monoid
(with one-dimensional center) forms a highest weight category, in the sense of
Cline, Parshall, and Scott. This is a fundamental fact about the representation
theory of reductive normal algebraic monoids. We survey how this result was
obtained, and treat some natural examples coming from classical groups.Comment: 10 pages. To appear in a volume of the Fields Communications Series:
"Algebraic Monoids, Group Embeddings, and Algebraic Combinatorics," edited by
Mahir Can, Zhenheng Li, Benjamin Steinberg, and Qiang Wan
The locality of the fourth root of staggered fermion determinant in the interacting case
The fourth root approximation in LQCD simulations with dynamical staggered
fermions requires justification. We test its validity numerically in the
interacting theory in a renormalization group framework.Comment: 6 pages, Talk presented at Lattice 2005 (Machines and Algorithms
Tunneling Study of the Charge-Ordering Gap on the Surface of LaPrCaMnO Thin Films
Variable temperature scanning tunneling microscopy/spectroscopy studies on
(110) oriented epitaxial thin films of
LaPrCaMnO are reported in the temperature
range of 77 to 340 K. The films, grown on lattice matched NdGaO substrates,
show a hysteretic metal-insulator transition in resistivity at 170 K. The
topographic STM images show step-terrace morphology while the conductance
images display a nearly homogeneous surface. The normalized conductance spectra
at low temperatures (T150 K) show an energy gap of 0.5 eV while for
T180 K a gap of 0.16 eV is found from the activated behavior of the zero
bias conductance. The presence of energy gap and the absence of phase
separation on the surface over more than 2 m2 m area
contradicts the metallic behavior seen in resistivity measurements at low
temperatures. We discuss the measured energy gap in terms of the stabilization
of the insulating CO phase at the film surface.Comment: 5 pages, 5 figures To appear in Phys. Rev.
The QCD equation of state with asqtad staggered fermions
We report on our result for the equation of state (EOS) with a Symanzik
improved gauge action and the asqtad improved staggered fermion action at
and 6. In our dynamical simulations with 2+1 flavors we use the inexact
R algorithm and here we estimate the finite step-size systematic error on the
EOS. Finally we discuss the non-zero chemical potential extension of the EOS
and give some preliminary results.Comment: 7 pages, 6 figures, presented at Lattice2006(High Temperature and
Density), to appear in Proceedings of Scienc
Barriers to Physical Activity: Physical Activity in Military Employees; Barrier impact on Perceived Health
Much of the world faces a growing obesity epidemic. (pp92-97) The consequences of this serious problem are well established and potentially devastating. Conditions associated with an elevated body mass include diabetes, hypertension, coronary heart disease, and certain malignancies.(pp97-100), For many, obesity and elevated body mass are a consequence of decreased physical activity; industrial advancements (eg, convenient transportation, technological advancements, and decreased need for manual labor) have contributed to an overall decrease in physical activity worldwide
Baryon masses with improved staggered quarks
The MILC collaboration's simulations with improved staggered quarks are being
extended with runs at a lattice spacing of 0.06 fm with quark masses down to
one tenth the strange quark mass. We give a brief introduction to these new
simulations and the determination of the lattice spacing. Then we combine these
new runs with older results to study the masses of the nucleon and the Omega
minus in the continuum and chiral limits.Comment: 7 pages, proceedings from Lattice 2007 conferenc
Update on the physics of light pseudoscalar mesons
We present an update of the MILC investigation of the properties of light
pseudoscalar mesons using three flavors of improved staggered quarks. Results
are presented for the and leptonic decay constants, the CKM matrix
element , the up, down and strange quark masses, and the coefficients
of the chiral lagrangian. We have new data for lattice spacing fm with several values of the light quark mass down to one-tenth
the strange quark mass, higher statistics for fm with the
light quark mass equal to one-tenth the strange quark mass, and initial results
for our smallest lattice spacing, fm with light quark mass
two-fifths of the strange quark mass.Comment: 7 pages, 4 figures. To be published in Proceedings of Science
(Lattice 2006) 163 (2006
The Equation of State for QCD with 2+1 Flavors of Quarks
We report results for the interaction measure, pressure and energy density
for nonzero temperature QCD with 2+1 flavors of improved staggered quarks. In
our simulations we use a Symanzik improved gauge action and the Asqtad
improved staggered quark action for lattices with temporal extent and
6. The heavy quark mass is fixed at approximately the physical strange
quark mass and the two degenerate light quarks have masses or
. The calculation of the thermodynamic observables employs the integral
method where energy density and pressure are obtained by integration over the
interaction measure.Comment: 6 pages, 1 figure, 3 tables, contribution to the XXIIIrd
International Symposium on Lattice Field Theory, 25-30 July 2005, Trinity
College, Dublin, Irelan
The 2+1 flavor topological susceptibility from the asqtad action at 0.06 fm
We report new data for the topological susceptibility computed on 2+1 flavor
dynamical configurations with lattice spacing 0.06 fm, generated with the
asqtad action. The topological susceptibility is computed by HYP smearing and
compared with rooted staggered chiral perturbation theory as the pion mass goes
to zero. At 0.06 fm, the raw data is already quite close to the continuum
extrapolated values obtained from coarser lattices. These results provide a
further test of the asqtad action with rooted staggered flavors.Comment: 7 pages, 5 figures, talk presented at the XXV International Symposium
on Lattice Field Theory, July 30 - August 4, 2007, Regensburg, German
More evidence of localization in the low-lying Dirac spectrum
We have extended our computation of the inverse participation ratio of
low-lying (asqtad) Dirac eigenvectors in quenched SU(3). The scaling dimension
of the confining manifold is clearer and very near 3. We have also computed the
2-point correlator which further characterizes the localization.Comment: presented at Lattice2005(Topology and Confinement), Dublin, July
25-30, 2005, 6 pages, 3 figures, to appear in Proceedings of Scienc
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