110,444 research outputs found
Guiding-center Hall viscosity and intrinsic dipole moment along edges of incompressible fractional quantum Hall fluids
The discontinuity of guiding-center Hall viscosity (a bulk property) at edges
of incompressible quantum Hall fluids is associated with the presence of an
intrinsic electric dipole moment on the edge. If there is a gradient of drift
velocity due to a non-uniform electric field, the discontinuity in the induced
stress is exactly balanced by the electric force on the dipole. The total Hall
viscosity has two distinct contributions: a "trivial" contribution associated
with the geometry of the Landau orbits, and a non-trivial contribution
associated with guiding-center correlations.
We describe a relation between the guiding-center edge-dipole moment and
"momentum polarization", which relates the guiding-center part of the bulk Hall
viscosity to the "orbital entanglement spectrum(OES)". We observe that using
the computationally-more-onerous "real-space entanglement spectrum (RES)" just
adds the trivial Landau-orbit contribution to the guiding-center part. This
shows that all the non-trivial information is completely contained in the OES,
which also exposes a fundamental topological quantity = , the difference between the "chiral stress-energy anomaly" (or signed
conformal anomaly) and the chiral charge anomaly. This quantity characterizes
correlated fractional quantum Hall fluids, and vanishes in uncorrelated integer
quantum Hall fluids
Recursive relations for a quiver gauge theory
We study the recursive relations for a quiver gauge theory with the gauge
group with bifundamental fermions transforming as
. We work out the recursive relation for the amplitudes
involving a pair of quark and antiquark and gluons of each gauge group. We
realize directly in the recursive relations the invariance under the order
preserving permutations of the gluons of the first and the second gauge group.
We check the proposed relations for MHV, 6-point and 7-point amplitudes and
find the agreements with the known results and the known relations with the
single gauge group amplitudes. The proposed recursive relation is much more
efficient in calculating the amplitudes than using the known relations with the
amplitudes of the single gauge group.Comment: 33 pages and 2 figures, minor correction
Shape change of Galileo probe models in free-flight tests
Scale models of the Galileo Probe made of polycarbonate, AXF5Q graphite, carbon-carbon composite, and carbon-phenolic were flown in a free flight range in an ambient gas of air, krypton, or xenon. Mach numbers varied between 14 and 24, Reynolds numbers between 300,000 and 1,000,000, stagnation pressures between 31 and 200 atm, and stagnation point heat transfer rates between 10 and 1,000 kW/sq cm. Shadowgraphs indicate gouging ablation of the aft portion of the frustum; the gouging was moderate in air and severe in the noble gases. The graphite models break in the same region. An explanation of the phenomena is offered in terms of the strong compression and shear caused by the reattachment of a turbulent separated flow. Conditions are calculated for similar tests appropriate for Von Karman Facility of the Arnold Engineering Development Center in which a larger model can be flown in argon
Remark on the effective potential of the gravitational perturbation in the black hole background projected on the brane
The polar perturbation is examined when the spacetime is expressed by a 4d
metric induced from higher-dimensional Schwarzschild geometry. Since the
spacetime background is not a vacuum solution of 4d Einstein equation, the
various general principles are used to understand the behavior of the
energy-momentum tensor under the perturbation. It is found that although the
general principles fix many components, they cannot fix two components of the
energy-momentum tensor. Choosing two components suitably, we derive the
effective potential which has a correct 4d limit.Comment: 12 pages, no figure, CQG accepte
Analysis, preliminary design and simulation systems for control-structure interaction problems
Software aspects of control-structure interaction (CSI) analysis are discussed. The following subject areas are covered: (1) implementation of a partitioned algorithm for simulation of large CSI problems; (2) second-order discrete Kalman filtering equations for CSI simulations; and (3) parallel computations and control of adaptive structures
Non-renormalization of two and three Point Correlators of N=4 SYM in N=1 Superspace
Certain two and three point functions of gauge invariant primary operators of
SYM are computed in superspace keeping all the
-components. This allows one to read off many component descendent
correlators. Our results show the only possible corrections to the
free field correlators are contact terms. Therefore they vanish for operators
at separate points, verifying the known non-renormalization theorems. This also
implies the results are consistent with supersymmetry even though
the Lagrangian we use has only manifest supersymmetry. We repeat
some of the calculations using supersymmetric Landau gauge and obtain, as
expected, the same results as those of supersymmetric Feynman gauge.Comment: 10 pages, 20 eps figures, references adde
Implementation of a partitioned algorithm for simulation of large CSI problems
The implementation of a partitioned numerical algorithm for determining the dynamic response of coupled structure/controller/estimator finite-dimensional systems is reviewed. The partitioned approach leads to a set of coupled first and second-order linear differential equations which are numerically integrated with extrapolation and implicit step methods. The present software implementation, ACSIS, utilizes parallel processing techniques at various levels to optimize performance on a shared-memory concurrent/vector processing system. A general procedure for the design of controller and filter gains is also implemented, which utilizes the vibration characteristics of the structure to be solved. Also presented are: example problems; a user's guide to the software; the procedures and algorithm scripts; a stability analysis for the algorithm; and the source code for the parallel implementation
Formulation of the information capacity of the optical-mechanical line-scan imaging process
An expression for the information capacity of the optical-mechanical line-scan imaging process is derived which includes the effects of blurring of spatial, photosensor noise, aliasing, and quantization. Both the information capacity for a fixed data density and the information efficiency (the ratio of information capacity to data density) exhibit a distinct single maximum when displayed as a function of sampling rate, and the location of this maximum was determined by the system frequency-response shape, signal-to-noise ratio, and quantization interval
A spectral reflectance estimation technique using multispectral data from the Viking lander camera
A technique is formulated for constructing spectral reflectance curve estimates from multispectral data obtained with the Viking lander camera. The multispectral data are limited to six spectral channels in the wavelength range from 0.4 to 1.1 micrometers and most of these channels exhibit appreciable out-of-band response. The output of each channel is expressed as a linear (integral) function of the (known) solar irradiance, atmospheric transmittance, and camera spectral responsivity and the (unknown) spectral responsivity and the (unknown) spectral reflectance. This produces six equations which are used to determine the coefficients in a representation of the spectral reflectance as a linear combination of known basis functions. Natural cubic spline reflectance estimates are produced for a variety of materials that can be reasonably expected to occur on Mars. In each case the dominant reflectance features are accurately reproduced, but small period features are lost due to the limited number of channels. This technique may be a valuable aid in selecting the number of spectral channels and their responsivity shapes when designing a multispectral imaging system
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