16,260 research outputs found
Exact Expressions for Minor Hysteresis Loops in the Random Field Ising Model on a Bethe Lattice at Zero Temperature
We obtain exact expressions for the minor hysteresis loops in the
ferromagnetic random field Ising model on a Bethe lattice at zero temperature
in the case when the driving field is cycled infinitely slowly.Comment: Replaced with the published versio
Self-Dual Chiral Boson: Augmented Superfield Approach
We exploit the standard tools and techniques of the augmented version of
Bonora-Tonin (BT) superfield formalism to derive the off-shell nilpotent and
absolutely anticommuting (anti-)BRST and (anti-)co-BRST symmetry
transformations for the Becchi-Rouet-Stora-Tyutin (BRST) invariant Lagrangian
density of a self-dual bosonic system. In the derivation of the full set of the
above transformations, we invoke the (dual-)horizontality conditions,
(anti-)BRST and (anti-)co-BRST invariant restrictions on the superfields that
are defined on the (2, 2)-dimensional supermanifold. The latter is
parameterized by the bosonic variable x^\mu\,(\mu = 0,\, 1) and a pair of
Grassmanian variables \theta and \bar\theta (with \theta^2 = \bar\theta^2 = 0
and \theta\bar\theta + \bar\theta\theta = 0). The dynamics of this system is
such that, instead of the full (2, 2) dimensional superspace coordinates
(x^\mu, \theta, \bar\theta), we require only the specific (1, 2)-dimensional
super-subspace variables (t, \theta, \bar\theta) for its description. This is a
novel observation in the context of superfield approach to BRST formalism. The
application of the dual-horizontality condition, in the derivation of a set of
proper (anti-)co-BRST symmetries, is also one of the new ingredients of our
present endeavor where we have exploited the augmented version of superfield
formalism which is geometrically very intuitive.Comment: LaTeX file, 27 pages, minor modifications, Journal reference is give
Superspace Unitary Operator in QED with Dirac and Complex Scalar Fields: Superfield Approach
We exploit the strength of the superspace (SUSP) unitary operator to obtain
the results of the application of the horizontality condition (HC) within the
framework of augmented version of superfield formalism that is applied to the
interacting systems of Abelian 1-form gauge theories where the U(1) Abelian
1-form gauge field couples to the Dirac and complex scalar fields in the
physical four (3 + 1)-dimensions of spacetime. These interacting theories are
generalized onto a (4, 2)-dimensional supermanifold that is parametrized by the
four (3 + 1)-dimensional (4D) spacetime variables and a pair of Grassmannian
variables. To derive the (anti-)BRST symmetries for the matter fields, we
impose the gauge invariant restrictions (GIRs) on the superfields defined on
the (4, 2)-dimensional supermanifold. We discuss various outcomes that emerge
out from our knowledge of the SUSP unitary operator and its hermitian
conjugate. The latter operator is derived without imposing any operation of
hermitian conjugation on the parameters and fields of our theory from outside.
This is an interesting observation in our present investigation.Comment: LaTeX file, 11 pages, journal versio
Exact Solution of Return Hysteresis Loops in One Dimensional Random Field Ising Model at Zero Temperature
Minor hysteresis loops within the main loop are obtained analytically and
exactly in the one-dimensional ferromagnetic random field Ising-model at zero
temperature. Numerical simulations of the model show excellent agreement with
the analytical results
Winter and summer simulations with the GLAS climate model
The GLAS climate model is a general circulation model based on the primitive equations in sigma coordinates on a global domain in the presence of orography. The model incorporates parameterizations of the effects of radiation, convection, large scale latent heat release, turbulent and boundary layer fluxes, and ground hydrology. Winter and summer simulations were carried out with this model, and the resulting data are compared to observations
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