3,259 research outputs found
Dimensional reduction in QCD: Lessons from lower dimensions
In this contribution we present the results of a series of investigations of
dimensional reduction, applied to SU(3) gauge theory in 2 + 1 dimensions. We
review earlier results, present a new reduced model with Z(3) symmetry, and
discuss the results of numerical simulations of this model.Comment: 10 pages, Talk given at Workshop on Finite Density QCD, Nara Japan
10-12 Jul 200
Z(3) Symmetric Dimensional Reduction of (2+1)D QCD
Here we present a candidate for a Z(3)-symmetric reduced action for the
description of the (2+1)D SU(3) gauge theoryComment: 2 pages, Statistical QCD pro
Three dimensional finite temperature SU(3) gauge theory in the confined region and the string picture
We determine the correlation between Polyakov loops in three dimensional
SU(3) gauge theory in the confined region at finite temperature. For this
purpose we perform lattice calculations for the number of steps in the
temperature direction equal to six. This is expected to be in the scaling
region of the lattice theory. We compare the results to the bosonic string
model. The agreement is very good for temperatures T<0.7T_c, where T_c is the
critical temperature. In the region 0.7T_c<T<T_c we enter the critical region,
where the critical properties of the correlations are fixed by universality to
be those of the two dimensional three state Potts model. Nevertheless, by
calculating the critical lattice coupling, we show that the ratio of the
critical temperature to the square root of the zero temperature string tension,
where the latter is taken from the literature, remains very near to the string
model prediction.Comment: 11 pages, 1 figure, 1 tabl
Critical Behaviour of the 3d Gross-Neveu and Higgs-Yukawa Models
We measure the critical exponents of the three dimensional Gross-Neveu model
with two four-component fermions. The exponents are inferred from the scaling
behaviour of observables on different lattice sizes. We also calculate the
exponents, through a second order epsilon-expansion around 4d, for the three
dimensional Higgs-Yukawa model, which is expected to be in the same
universality class and we find that the exponents agree. We conclude that the
equivalence of the two models remains valid in 3d at fixed small N_f values.Comment: 14 Latex pages 8 PSfigures included at the
end,BI-TP-93/31,AZPH-TH/93-19,SPhT 93/0
Dimensional reduction and a Z(3) symmetric model
We present first results from a numerical investigation of a Z(3) symmetric
model based on dimensional reduction.Comment: Talk presented at XXI International Symposium on Lattice Field Theory
lattice2003(Non-zero temperature and density
QCD with Adjoint Scalars in 2D: Properties in the Colourless Scalar Sector
We present a numerical study of an SU(3) gauged 2D model for adjoint scalar
fields, defined by dimensional reduction of pure gauge QCD in (2+1)D at high
temperature. In the symmetric phase of its global Z_2 symmetry, two colourless
boundstates, even and odd under Z_2, are identified. Their respective
contributions (poles) in correlation functions of local composite operators A_n
of degree n=2p and 2p+1 in the scalar fields (p=1,2) fulfill factorization. The
contributions of two particle states (cuts) are detected. Their size agrees
with estimates based on a meanfield-like decomposition of the p=2 operators
into polynomials in p=1 operators. No sizable signal in any A_n correlation can
be attributed to 1/n times a Debye screening length associated with n
elementary fields. These results are quantitatively consistent with the picture
of scalar ``matter'' fields confined within colourless boundstates whose
residual ``strong'' interactions are very weak.Comment: 27 pages, improved presentation of results and some references added,
as accepted by Nucl. Phys.
Screening Masses in Dimensionally Reduced (2+1)D Gauge Theory
We discuss the screening masses and residue factorisation of the SU(3) (2+1)D
theory in the dimensional reduction formalism. The phase structure of the
reduced model is also investigated.Comment: 3 pages, Lattice 2001(gaugetheories
A matter of time: Implicit acquisition of recursive sequence structures
A dominant hypothesis in empirical research on the evolution of language is the following: the fundamental difference between animal and human communication systems is captured by the distinction between regular and more complex non-regular grammars. Studies reporting successful artificial grammar learning of nested recursive structures and imaging studies of the same have methodological shortcomings since they typically allow explicit problem solving strategies and this has been shown to account for the learning effect in subsequent behavioral studies. The present study overcomes these shortcomings by using subtle violations of agreement structure in a preference classification task. In contrast to the studies conducted so far, we use an implicit learning paradigm, allowing the time needed for both abstraction processes and consolidation to take place. Our results demonstrate robust implicit learning of recursively embedded structures (context-free grammar) and recursive structures with cross-dependencies (context-sensitive grammar) in an artificial grammar learning task spanning 9 days. Keywords: Implicit artificial grammar learning; centre embedded; cross-dependency; implicit learning; context-sensitive grammar; context-free grammar; regular grammar; non-regular gramma
Wild Pfister forms over Henselian fields, K-theory, and conic division algebras
The epicenter of this paper concerns Pfister quadratic forms over a field
with a Henselian discrete valuation. All characteristics are considered but we
focus on the most complicated case where the residue field has characteristic 2
but does not. We also prove results about round quadratic forms,
composition algebras, generalizations of composition algebras we call conic
algebras, and central simple associative symbol algebras. Finally we give
relationships between these objects and Kato's filtration on the Milnor
-groups of
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