95,706 research outputs found
Non-Gaussian statistics, maxwellian derivation and stellar polytropes
In this letter we discuss the Non-gaussian statistics considering two
aspects. In the first, we show that the Maxwell's first derivation of the
stationary distribution function for a dilute gas can be extended in the
context of Kaniadakis statistics. The second one, by investigating the stellar
system, we study the Kaniadakis analytical relation between the entropic
parameter and stellar polytrope index . We compare also the
Kaniadakis relation with proposed in the Tsallis
framework.Comment: 10 pages, 1 figur
Comparing a current-carrying circular wire with polygons of equal perimeter; Magnetic field versus magnetic flux
We compare the magnetic field at the center of and the self-magnetic flux
through a current-carrying circular loop, with those obtained for
current-carrying polygons with the same perimeter. As the magnetic field
diverges at the position of the wires, we compare the self-fluxes utilizing
several regularization procedures. The calculation is best performed utilizing
the vector potential, thus highlighting its usefulness in practical
applications. Our analysis answers some of the intuition challenges students
face when they encounter a related simple textbook example. These results can
be applied directly to the determination of mutual inductances in a variety of
situations.Comment: 9 pages, 4 figure
Gribov copies, Lattice QCD and the gluon propagator
We address the problem of Gribov copies in lattice QCD. The gluon propagator
is computed, in the Landau gauge, using 302 ()
configurations gauge fixed to different copies. The results of the simulation
shows that: i) the effect of Gribov copies is small (less than 10%); ii) Gribov
copies change essentially the lowest momenta components ( GeV); iii)
within the statistical accuracy of our simulation, the effect of Gribov copies
is resolved if statistical errors are multiplied by a factor of two or three.
Moreover, when modelling the gluon propagator, different sets of Gribov copies
produce different sets of parameters not, necessarily, compatible within one
standard deviation. Finally, our data supports a gluon propagator which, for
large momenta, behaves like a massive gluon propagator with a mass of 1.1 GeV
The Infrared Landau Gauge Gluon Propagator from Lattice QCD
The quenched Landau gauge gluon propagator is investigated in lattice QCD
with large assimetric lattices, accessing momenta as low as MeV or
smaller. Our investigation focus on the IR limit of the gluon dressing
function, testing the compatibility with recent solutions of the
Dyson-Schwinger equations. In particular, the low energy parameters
and are measured.Comment: 3 pages, 1 figure. Talk given at Quark Confinement and the Hadron
Spectrum VI 2004, Italy, 21-25 Sep. References correc
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