3,839 research outputs found
Infrared analysis of propagators and vertices of Yang--Mills theory in Landau and Coulomb gauge
The infrared behaviour of gluon and ghost propagators, ghost-gluon vertex and
three-gluon vertex is investigated for both the covariant Landau and the
non-covariant Coulomb gauge. Assuming infrared ghost dominance, we find a
unique infrared exponent in the d=4 Landau gauge, while in the d=3+1 Coulomb
gauge we find two different infrared exponents. We also show that a finite
dressing of the ghost-gluon vertex has no influence on the infrared exponents.
Finally, we determine the infrared behaviour of the three-gluon vertex
analytically and calculate it numerically at the symmetric point in the Coulomb
gauge.Comment: 25 pages, 6 figures, accepted by Phys. Rev. D, references added,
typos correcte
Color Coulomb Potential in Yang-Mills Theory from Hamiltonian Flows
We consider the Hamiltonian formulation of Yang-Mills theory in the Coulomb
gauge and apply the recently developed technique of Hamiltonian flows. We
formulate a flow equation for the color Coulomb potential which allows for a
scaling solution that results in an almost linearly rising confining potential.Comment: 6 pages, 4 figure
Vibrations on pulse tube based Dry Dilution Refrigerators for low noise measurements
Dry Dilution Refrigerators (DDR) based on pulse tube cryo-coolers have
started to replace Wet Dilution Refrigerators (WDR) due to the ease and low
cost of operation. However these advantages come at the cost of increased
vibrations, induced by the pulse tube. In this work, we present the vibration
measurements performed on three different commercial DDRs. We describe in
detail the vibration measurement system we assembled, based on commercial
accelerometers, conditioner and DAQ, and examined the effects of the various
damping solutions utilized on three different DDRs, both in the low and high
frequency regions. Finally, we ran low temperature, pseudo-massive (30 and 250
g) germanium bolometers in the best vibration-performing system under study and
report on the results
Functional approaches to infrared Yang-Mills theory in the Coulomb gauge
We present the current status of ongoing efforts to use functional methods,
Dyson-Schwinger equations and functional renormalization group equations, for
the description of the infrared regime of nonabelian (pure) gauge theories in
the Coulomb gauge. In particular, we present a new determination of the
color-Coulomb potential with the help of the functional renormalization group
that results in an almost linearly rising potential between static color
charges at large spatial distances.Comment: 11 pages, 3 figures. Slightly improved version of J. Phys.: Conf.
Ser. 287 (2011) 01202
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