5,294 research outputs found
The bosonic string and superstring models in 26+2 and 10+2 dimensional space--time, and the generalized Chern-Simons action
We have covariantized the Lagrangians of the U(1)_V * U(1)_A models, which
have U(1)_V * U(1)_A gauge symmetry in two dimensions, and studied their
symmetric structures. The special property of the U(1)_V * U(1)_A models is the
fact that all these models have an extra time coordinate in the target
space-time. The U(1)_V * U(1)_A models coupled to two-dimensional gravity are
string models in 26+2 dimensional target space-time for bosonic string and in
10+2 dimensional target space-time for superstring. Both string models have two
time coordinates. In order to construct the covariant Lagrangians of the U(1)_V
* U(1)_A models the generalized Chern-Simons term plays an important role. The
supersymmetric generalized Chern-Simons action is also proposed. The
Green-Schwarz type of U(1)_V * U(1)_A superstring model has another fermionic
local symmetry as well as \kappa-symmetry. The supersymmetry of target
space-time is different from the standard one.Comment: 27 pages, no figure
Dirac-Kaehler fermion with noncommutative differential forms on a lattice
Noncommutativity between a differential form and a function allows us to
define differential operator satisfying Leibniz's rule on a lattice. We propose
a new associative Clifford product defined on the lattice by introducing the
noncommutative differential forms. We show that this Clifford product naturally
leads to the Dirac-K\"ahler fermion on the lattice.Comment: 3 pages, Lattice2003(Theoretical Development
N=2 Supersymmetric Model with Dirac-Kahler Fermions from Generalized Gauge Theory in Two Dimensions
We investigate the generalized gauge theory which has been proposed
previously and show that in two dimensions the instanton gauge fixing of the
generalized topological Yang-Mills action leads to a twisted N=2 supersymmetric
action. We have found that the R-symmetry of N=2 supersymmetry can be
identified with the flavour symmetry of Dirac-Kahler fermion formulation. Thus
the procedure of twist allows topological ghost fields to be interpreted as the
Dirac-Kahler matter fermions.Comment: 22 pages, LaTe
Note on Dirac--K\"ahler massless fields
We obtain the canonical and symmetrical Belinfante energy-momentum tensors of
Dirac--K\"{a}hler's fields. It is shown that the traces of the energy-momentum
tensors are not equal to zero. We find the canonical and Belinfante dilatation
currents which are not conserved, but a new conserved dilatation current is
obtained. It is pointed out that the conformal symmetry is broken. The
canonical quantization is performed and the propagator of the massless fields
in the first-order formalism is found.Comment: 16 pages, minor corrections in the text, published versio
Comparing high-resolution gridded precipitation data with satellite rainfall estimates of TRMM_3B42 over Iran
To evaluate satellite rainfall estimates of Tropical Rain
Measurement Mission (TRMM) level 3 output (3B42) (TRMM_3B42) over Iran
(20°â€“45° N, 40°â€“65° E), we compared these data with
high-resolution gridded precipitation datasets (0.25°×0.25° latitude/longitude) based on rain gauges (Iran Synoptic gauges Version 0902
(IS0902)). Spatial distribution of mean annual and mean seasonal rainfall in
both IS0902 and TRMM_3B42 from 1998 to 2006 shows two main rainfall
patterns along the Caspian Sea and over the Zagros Mountains. Scatter plots
of annual average rainfall from IS0902 versus TRMM_3B42 for each 0.25°×0.25° grid cell
over the entire country (25°â€“40° N,
45°â€“60° E), along the Caspian Sea (35°â€“40° N, 48°â€“56° E), and
over the Zagros Mountains (28°â€“37° N, 46°â€“55° E)
were derived. For the entire country, the Caspian Sea region, and the Zagros
Mountains, TRMM_3B42 underestimates mean annual precipitation by 0.17,
0.39, and 0.15 mm day<sup>−1</sup>, respectively, and the mean annual rainfall
spatial correlation coefficients are 0.77, 0.57, and 0.75, respectively. The
mean annual precipitation temporal correlation coefficient for IS0902 and
TRMM_3B42 is ~0.8 in the area along the Zagros Mountains, and ~0.6
in the Caspian Sea and desert regions
Species Doublers as Super Multiplets in Lattice Supersymmetry: Exact Supersymmetry with Interactions for D=1 N=2
We propose a new lattice superfield formalism in momentum representation
which accommodates species doublers of the lattice fermions and their bosonic
counterparts as super multiplets. We explicitly show that one dimensional N=2
model with interactions has exact Lie algebraic supersymmetry on the lattice
for all super charges. In coordinate representation the finite difference
operator is made to satisfy Leibnitz rule by introducing a non local product,
the ``star'' product, and the exact lattice supersymmetry is realized. The
standard momentum conservation is replaced on the lattice by the conservation
of the sine of the momentum, which plays a crucial role in the formulation.
Half lattice spacing structure is essential for the one dimensional model and
the lattice supersymmetry transformation can be identified as a half lattice
spacing translation combined with alternating sign structure. Invariance under
finite translations and locality in the continuum limit are explicitly
investigated and shown to be recovered. Supersymmetric Ward identities are
shown to be satisfied at one loop level. Lie algebraic lattice supersymmetry
algebra of this model suggests a close connection with Hopf algebraic exactness
of the link approach formulation of lattice supersymmetry.Comment: 34 pages, 2 figure
Formulation of Supersymmetry on a Lattice as a Representation of a Deformed Superalgebra
The lattice superalgebra of the link approach is shown to satisfy a Hopf
algebraic supersymmetry where the difference operator is introduced as a
momentum operator. The breakdown of the Leibniz rule for the lattice difference
operator is accommodated as a coproduct operation of (quasi)triangular Hopf
algebra and the associated field theory is consistently defined as a braided
quantum field theory. Algebraic formulation of path integral is perturbatively
defined and Ward-Takahashi identity can be derived on the lattice. The claimed
inconsistency of the link approach leading to the ordering ambiguity for a
product of fields is solved by introducing an almost trivial braiding structure
corresponding to the triangular structure of the Hopf algebraic superalgebra.
This could be seen as a generalization of spin and statistics relation on the
lattice. From the consistency of this braiding structure of fields a grading
nature for the momentum operator is required.Comment: 45 page
Determinant Structure of the Rational Solutions for the Painlev\'e IV Equation
Rational solutions for the Painlev\'e IV equation are investigated by Hirota
bilinear formalism. It is shown that the solutions in one hierarchy are
expressed by 3-reduced Schur functions, and those in another two hierarchies by
Casorati determinant of the Hermite polynomials, or by special case of the
Schur polynomials.Comment: 19 pages, Latex, using theorem.st
Reversible Metal-Semiconductor Transition of ssDNA-Decorated Single-Walled Carbon Nanotubes
A field effect transistor (FET) measurement of a SWNT shows a transition from
a metallic one to a p-type semiconductor after helical wrapping of DNA. Water
is found to be critical to activate this metal-semiconductor transition in the
SWNT-ssDNA hybrid. Raman spectroscopy confirms the same change in electrical
behavior. According to our ab initio calculations, a band gap can open up in a
metallic SWNT with wrapped ssDNA in the presence of water molecules due to
charge transfer.Comment: 13 pages, 6 figure
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