5,530 research outputs found
Dyson-Schwinger Equations and Coulomb Gauge Yang-Mills Theory
Coulomb gauge Yang-Mills theory is considered within the first order
formalism. It is shown that the action is invariant under both the standard BRS
transform and an additional component. The Ward-Takahashi identity arising from
this non-standard transform is shown to be automatically satisfied by the
equations of motion.Comment: 3 pages, talk given at Quark Confinement and the Hadron Spectrum VII
(2-7 Sep, 2006), Ponta Delgada, Azore
The ghost propagator in Coulomb gauge
We present results for a numerical study of the ghost propagator in Coulomb
gauge whereby lattice results for the spatial gluon propagator are used as
input to solving the ghost Dyson-Schwinger equation. We show that in order to
solve completely, the ghost equation must be supplemented by a boundary
condition (the value of the inverse ghost propagator dressing function at zero
momentum) which determines if the solution is critical (zero value for the
boundary condition) or subcritical (finite value). The various solutions
exhibit a characteristic behavior where all curves follow the same (critical)
solution when going from high to low momenta until `forced' to freeze out in
the infrared to the value of the boundary condition. The boundary condition can
be interpreted in terms of the Gribov gauge-fixing ambiguity; we also
demonstrate that this is not connected to the renormalization. Further, the
connection to the temporal gluon propagator and the infrared slavery picture of
confinement is discussed.Comment: 3 pages, 2 figures, talk presented at "Quark Confinement and the
Hadron Spectrum IX", Madrid, August 30-September 3, 2010, to appear in the
proceeding
Schwinger-Dyson equations and disorder
Using simple models in D=0+0 and D=0+1 dimensions we construct partition
functions and compute two-point correlations. The exact result is compared with
saddle-point approximation and solutions of Schwinger-Dyson equations. When
integrals are dominated by more than one saddle-point we find Schwinger-Dyson
equations do not reproduce the correct results unless the action is first
transformed into dual variables.Comment: 7 pages, 6 figure
Homogeneous TIP4P/2005 ice nucleation at low supercooling
We present a partial free energy profile for the homogeneous nucleation of
ice using an all-atom model of water at low supercooling, at which ice growth
dynamics are reasonably accessible to simulation. We demonstrate that the free
energy profile is well described by classical nucleation theory, and that the
nucleation barrier is entropic in origin. We also estimate to first order the
temperature dependence of the interfacial free energy
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