2,978 research outputs found
The Maximal Abelian Gauge, Monopoles, and Vortices in SU(3) Lattice Gauge Theory
We report on calculations of the heavy quark potential in SU(3) lattice gauge
theory. Full SU(3) results are compared to three cases which involve
gauge-fixing and projection. All of these start from the maximal abelian gauge
(MAG), in its simplest form. The first case is abelian projection to U(1)xU(1).
The second keeps only the abelian fields of monopoles in the MAG. The third
involves an additional gauge-fixing to the indirect maximal center gauge
(IMCG), followed by center projection to Z(3). At one gauge
fixing/configuration, the string tensions calculated from MAG U(1)xU(1), MAG
monopoles, and IMCG Z(3) are all less than the full SU(3) string tension. The
projected string tensions further decrease, by approximately 10%, when account
is taken of gauge ambiguities. Comparison is made with corresponding results
for SU(2). It is emphasized that the formulation of the MAG is more subtle for
SU(3) than for SU(2), and that the low string tensions may be caused by the
simple MAG form used. A generalized MAG for SU(3) is formulated.Comment: 22 pages, latex, 2 postscript figures. Replaced version has added
data at beta=6.0, analysis of Gribov ambiguities, extended tables of results,
discussion of scalin
The Spatial String Tension in the Deconfined Phase of the (3+1)-Dimensional SU(2) Gauge Theory
We present results of a detailed investigation of the temperature dependence
of the spatial string tension in SU(2) gauge theory. We show, for the first
time, that the spatial string tension is scaling on the lattice and thus is
non-vanishing in the continuum limit. It is temperature independent below Tc
and rises rapidly above. For temperatures larger than 2Tc we find a scaling
behaviour consistent with sigma_s(T) = 0.136(11) g^4(T) T^2, where g(T) is the
2-loop running coupling constant with a scale parameter determined as Lambda_T
= 0.076(13) Tc.Comment: 8 pages (Latex, shell archive, 3 PostScript figures), HLRZ-93-43,
BI-TP 93/30, FSU-SCRI-93-76, WUB 93-2
Description with a Screened Potential
Recent lattice QCD calculations suggest a rather abrupt transition in the
confinig potential from a linear to a constant behavior. We analyze the effects
of such a fast deconfinement in the simplest non-relativistic system,
bottomonium.Comment: 4 pages. Presented at MENU04, Beijing 2004. To be published by IJMP
Lattice energy sum rules and the trace anomaly
We show that the additional contribution to the Michael lattice energy sum
rule for the static quark-antiquark potential, pointed out recently, can be
identified with the contribution to the field energy arising from the trace
anomaly of the energy momentum tensor. We also exlicitely exhibit the anomalous
contribution to the field energy in the sum rule for the glueball mass obtained
recently by Michael.Comment: 8 pages, plain TeX, no figures; text & abstract extended. Includes
glueball energy sum rul
What is it like to learn and participate in rhizomatic MOOCs? a collaborative autoethnography of #RHIZO14
In January 2014, we participated in a connectivist-style massive open online course (cMOOC) called "Rhizomatic Learning â The community is the curriculum" (#rhizo14). In rhizomatic learning, teacher and student roles are radically restructured. Course content and value come mostly from students; the teacher, at most, is a curator who provides a starting point and guidance and sometimes participates as a learner. Early on, we felt that we were in a unique learning experience that we wanted to capture in writing. Explaining #rhizo14 to others without the benefit of traditional processes, practices, roles, or structures, however, presented a challenge. We invited participants to contribute narratives to a collaborative autoethnography (CAE), which comprises an assortment of collaborative Google Docs, blog posts by individuals, and comments on those documents and posts. This strategy afforded insight into what many participants found to be a most engaging course and what for some was a transformative experience. In discussing the findings from the CAE, our intent is to benefit others interested in rhizomatic learning spaces such as cMOOCs. This authoethnography specifically addresses gaps both in the understanding of the learner experience in cMOOCs and in the nature of rhizomatic learning
The scalar and tensor glueballs in the valence approximation
We evaluate the infinite volume, continuum limit of and
glueball masses in the valence approximation. We find ~MeV and ~MeV, consistent with the interpretation
of as the lightest scalar glueball.Comment: (talk presented by A. Vaccarino at Lattice 93) 3 pages of PostScript
in uufiles compressed form. IBM-HET-94-
Cylindrically Symmetric Inhomogeneous Universes with a Cloud of Strings
Cylindrically symmetric inhomogeneous string cosmological models are
investigated in presence of string fluid as a source of matter. To get the
three types of exact solutions of Einstein's field equations we assume , and . Some physical and geometric
aspects of the models are discussed.Comment: 9 page
Gluon propagator, triple gluon vertex and the QCD coupling constant
We study the UV-scaling of the flavorless gluon propagator in the Landau
gauge in an energy window up to 9 GeV. Dominant hypercubic lattice artifacts
are eliminated. A large set of renormalization schemes is used to test
asymptotic scaling. We compare with our results obtained directly from the
triple gluon vertex. We end-up with \Lambda_{\bar{\rm{MS}}} = 318(12)(5) MeV
and 292(5)(15) MeV respectively for these two methods, compatible which each
other but significantly above the Schrodinger method estimate.Comment: 3 pages, LaTeX with two figures; presented at LATTICE9
A Tachyonic Gluon Mass: Between Infrared and Ultraviolet
The gluon spin coupling to a Gaussian correlated background gauge field
induces an effective tachyonic gluon mass. It is momentum dependent and
vanishes in the UV only like 1/p^2. In the IR, we obtain stabilization through
a positive m^2_{conf}(p^2) related to confinement. Recently a purely
phenomenological tachyonic gluon mass was used to explain the linear rise in
the q\bar q static potential at small distances and also some long standing
discrepancies found in QCD sum rules. We show that the stochastic vacuum model
of QCD predicts a gluon mass with the desired properties.Comment: 10 pages LaTeX, 2 figures using eps
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