Partition functions of Supersymmetric Gauge Theories in Noncommutative R^{2D} and their Unified Perspective

We investigate cohomological gauge theories in noncommutative R^{2D}. We show that vacuum expectation values of the theories do not depend on noncommutative parameters, and the large noncommutative parameter limit is equivalent to the dimensional reduction. As a result of these facts, we show that a partition function of a cohomological theory defined in noncommutative R^{2D} and a partition function of a cohomological field theory in R^{2D+2} are equivalent if they are connected through dimensional reduction. Therefore, we find several partition functions of supersymmetric gauge theories in various dimensions are equivalent. Using this technique, we determine the partition function of the N=4 U(1) gauge theory in noncommutative R^4, where its action does not include a topological term. The result is common among (8-dim, N=2), (6-dim, N=2), (2-dim, N=8) and the IKKT matrix model given by their dimensional reduction to 0-dim.Comment: 45 pages, no figures, Appendices B and C are added, changes in the text, references are adde

Earthquake Induced Slope Failure Simulation by SPH

Majority of slope stability, slope displacement and soil liquefaction analyses subjected to earthquake loading condition employed the finite element method (FEM) as the standard numerical tool. However, mechanism of soil failure in such condition often involved extremely large deformation and failure behaviors, which were unable to be modeled by FEM since this method was suffered from the grid distortion. In an attempt to overcome this limitation, we present herein our first attempt to extend the smoothed particle hydrodynamics (SPH) method to analyze slope failure behavior due to seismic shaking. For the sake of simplicity, effect of pore-water pressure was not taken into consideration. The numerical framework was then applied to simulate the failure behavior of a slope subjected to a seismic loading. Experimental model was also conducted to verify the numerical performance. It is shown that SPH can simulate fairly well the slope failure behavior in the model test, especially in prediction of the failure surface. The paper suggests that SPH should be considered as a powerful alternative for computation of geomaterials subjected to earthquake loading conditions

Resolved 24.5 micron emission from massive young stellar objects

Massive young stellar objects (MYSO) are surrounded by massive dusty envelopes. Our aim is to establish their density structure on scales of ~1000 AU, i.e. a factor 10 increase in angular resolution compared to similar studies performed in the (sub)mm. We have obtained diffraction-limited (0.6") 24.5 micron images of 14 well-known massive star formation regions with Subaru/COMICS. The images reveal the presence of discrete MYSO sources which are resolved on arcsecond scales. For many sources, radiative transfer models are capable of satisfactorily reproducing the observations. They are described by density powerlaw distributions (n(r) ~ r^(-p)) with p = 1.0 +/-0.25. Such distributions are shallower than those found on larger scales probed with single-dish (sub)mm studies. Other sources have density laws that are shallower/steeper than p = 1.0 and there is evidence that these MYSOs are viewed near edge-on or near face-on, respectively. The images also reveal a diffuse component tracing somewhat larger scale structures, particularly visible in the regions S140, AFGL 2136, IRAS 20126+4104, Mon R2, and Cep A. We thus find a flattening of the MYSO envelope density law going from ~10 000 AU down to scales of ~1000 AU. We propose that this may be evidence of rotational support of the envelope (abridged).Comment: 21 pages, accepted for A&