2,960 research outputs found
Noncommutative Deformation of Spinor Zero Mode and ADHM Construction
A method to construct noncommutative instantons as deformations from
commutative instantons was provided in arXiv:0805.3373. Using this
noncommutative deformed instanton, we investigate the spinor zero modes of the
Dirac operator in a noncommutative instanton background on noncommutative R^4,
and we modify the index of the Dirac operator on the noncommutative space
slightly and show that the number of the zero mode of the Dirac operator is
preserved under the noncommutative deformation. We prove the existence of the
Green's function associated with instantons on noncommutative R^4, as a smooth
deformation of the commutative case. The feature of the zero modes of the Dirac
operator and the Green's function derives noncommutative ADHM equations which
coincide with the ones introduced by Nekrasov and Schwarz. We show a one-to-one
correspondence between the instantons on noncommutative R^4 and ADHM data. An
example of a noncommutative instanton and a spinor zero mode are also given.Comment: 34 pages, no figures, v3: an appendix and some definitions
added,typos correcte
The Soft X-ray Spectrum from NGC 1068 Observed with LETGS on Chandra
Using the combined spectral and spatial resolving power of the Low Energy
Transmission Grating (LETGS) on board Chandra, we obtain separate spectra from
the bright central source of NGC 1068 (Primary region), and from a fainter
bright spot 4" to the NE (Secondary region). Both spectra are dominated by line
emission from H- and He-like ions of C through S, and from Fe L-shell ions, but
also include narrow radiative recombination continua, indicating that most of
the soft X-ray emission arises in low-temperature (kT few eV) photoionized
plasma. We confirm the conclusions of Kinkhabwala et al. (2002), based on
XMM-Newton RGS observations, that the entire nuclear spectrum can be explained
by recombination/radiative cascade following photoionization, and radiative
decay following photoexcitation, with no evidence for hot, collisionally
ionized plasma. In addition, this model also provides an excellent fit to the
spectrum of the Secondary region, albeit with radial column densities a factor
of three lower, as would be expected given its distance from the source of the
ionizing continuum. The remarkable overlap and kinematical agreement of the
optical and X-ray line emission, coupled with the need for a distribution of
ionization parameter to explain the X-ray spectra, collectively imply the
presence of a distribution of densities (over a few orders of magnitude) at
each radius in the ionization cone. Relative abundances of all elements are
consistent with Solar abundance, except for N, which is 2-3 times Solar. The
long wavelength spectrum beyond 30 A is rich of L-shell transitions of Mg, Si,
S, and Ar, and M-shell transitions of Fe. The velocity dispersion decreases
with increasing ionization parameter, as deduced from these long wavelength
lines and the Fe-L shell lines.Comment: 12 pages, 11 figures, accepted for publication in Astronomy and
Astrophysic
Gauge Theories in Noncommutative Homogeneous K\"ahler Manifolds
We construct a gauge theory on a noncommutative homogeneous K\"ahler
manifold, where we employ the deformation quantization with separation of
variables for K\"ahler manifolds formulated by Karabegov. A key point in this
construction is to obtaining vector fields which act as inner derivations for
the deformation quantization. We show that these vector fields are the only
Killing vector fields. We give an explicit construction of this gauge theory on
noncommutative and noncommutative .Comment: 27 pages, typos correcte
Euler number of Instanton Moduli space and Seiberg-Witten invariants
We show that a partition function of topological twisted N=4 Yang-Mills
theory is given by Seiberg-Witten invariants on a Riemannian four manifolds
under the condition that the sum of Euler number and signature of the four
manifolds vanish. The partition function is the sum of Euler number of
instanton moduli space when it is possible to apply the vanishing theorem. And
we get a relation of Euler number labeled by the instanton number with
Seiberg-Witten invariants, too. All calculation in this paper is done without
assuming duality.Comment: LaTeX, 34 page
Analisis Faktor-faktor yang Mempengaruhi Produksi Industri Tapioka (Studi Kasus Pt.hutahaean Kec Laguboti, Kab Toba Samosir, Sumatera Utara)
This study aimed to analize the effecting factors of production industrial tapioca (case study sub-district Laguboti, regency Toba Samosir, North Sumatera). The study use seconder data. The analytical method that used in this study are quantitative descriptive method, partial analysis and simultaneous (multiple regression analysis model with Cobb-Douglas production with the help of the program SPSS version 21). Based on the result of the test, the regression simultaneous test (f test) shows that all of independent variable has the significant effect for the production of tapioca. The partial regression test (t test) shows that the capital variable has positive and not significant effect with the koifisien value of 0.006, raw material cost variable has positive and significant effect with the koifisien value of 0.269, and the engine variable has positive and significant effect for the production of the tapioca with koifisien value of 0,665. The effect that caused (R2) by the three variables by simultaneous for the production variable of the tapioca 96,5% meanwhile the other 3,5% effected by the other variable that not mentioned on the model
Microscopic simulation of membrane molecule diffusion on corralled membrane surfaces
The current understanding of how receptors diffuse and cluster in the plasma membrane is limited. Data from single-particle tracking and laser tweezer experiments have suggested that membrane molecule diffusion is affected by the presence of barriers dividing the membrane into corrals. Here, we have developed a stochastic spatial model to simulate the effect of corrals on the diffusion of molecules in the plasma membrane. The results of this simulation confirm that a fence barrier (the ratio of the transition probability for diffusion across a boundary to that within a corral) on the order of 103–104 recreates the experimentally measured difference in diffusivity between artificial and natural plasma membranes. An expression for the macroscopic diffusivity of receptors on corralled membranes is derived to analyze the effects of the corral parameters on diffusion rate. We also examine whether the lattice model is an appropriate description of the plasma membrane and look at three different sets of boundary conditions that describe diffusion over the barriers and whether diffusion events on the plasma membrane may occur with a physically relevant length scale. Finally, we show that to observe anomalous (two-timescale) diffusion, one needs high temporal (microsecond) resolution along with sufficiently long (more than milliseconds) trajectories
Air Shower Simulation and Hadronic Interactions
The aim of this report of the Working Group on Hadronic Interactions and Air
Shower Simulation is to give an overview of the status of the field,
emphasizing open questions and a comparison of relevant results of the
different experiments. It is shown that an approximate overall understanding of
extensive air showers and the corresponding hadronic interactions has been
reached. The simulations provide a qualitative description of the bulk of the
air shower observables. Discrepancies are however found when the correlation
between measurements of the longitudinal shower profile are compared to that of
the lateral particle distributions at ground. The report concludes with a list
of important problems that should be addressed to make progress in
understanding hadronic interactions and, hence, improve the reliability of air
shower simulations.Comment: Working Group report given at UHECR 2012 Symposium, CERN, Feb. 2012.
Published in EPJ Web of Conferences 53, 01007 (2013
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