4,450 research outputs found
Non-Abelian Stokes Theorem for Wilson Loops Associated with General Gauge Groups
A formula constituting the non-Abelian Stokes theorem for general semi-simple
compact gauge groups is presented. The formula involves a path integral over a
group space and is applicable to Wilson loop variables irrespective of the
topology of loops. Some simple expressions analogous to the 't Hooft tensor of
a magnetic monopole are given for the 2-form of interest. A special property in
the case of the fundamental representation of the group SU(N) is pointed out.Comment: 11 pages, PTPTEX, corrected some typo
Non-Abelian Stokes Theorem for Loop Variables Associated with Nontrivial Loops
The non-Abelian Stokes theorem for loop variables associated with nontrivial
loops (knots and links) is derived. It is shown that a loop variable is in
general different from unity even if the field strength vanishes everywhere on
the surface surrounded by the loop.Comment: 18 pages,10 Postscript figures, PTP Tex, Journal-ref adde
Consistency Conditions of the Faddeev-Niemi-Periwal Ansatz for the SU(N) Gauge Field
The consistency condition of the Faddeev-Niemi ansatz for the gauge-fixed
massless SU(2) gauge field is discussed. The generality of the ansatz is
demonstrated by obtaining a sufficient condition for the existence of the
three-component field introduced by Faddeev and Niemi. It is also shown that
the consistency conditions determine this three-component field as a functional
of two arbitrary functions. The consistency conditions corresponding to the
Periwal ansatz for the SU(N) gauge field with N larger than 2 are also
obtained. It is shown that the gauge field obeying the Periwal ansatz must
satisfy extra (N-1)(N-2)/2 conditions.Comment: PTP Tex, 15 pages, Eq.(3.18) inserte
Modal interpolation program, L215 (INTERP). Volume 1: Engineering and usage
The usage of the Modal Interpolation Program L215 (INTERP) is described. The program uses modal data to form sets of arrays containing interpolation coefficients. The interpolation arrays can then be used to determine displacements at various aerodynamic surface and surface slopes that are parallel and perpendicular to the freestream direction. Five different interpolation methods are available. A description of the data manipulation and the interpolation methods is presented
Landauer-B\"uttiker approach for hyperfine mediated electronic transport in the integer quantum Hall regime
The interplay of spin-polarized electronic edge states with the dynamics of
the host nuclei in quantum Hall systems presents rich and non-trivial transport
physics. Here, we develop a Landauer-B\"uttiker approach to understand various
experimental features observed in the integer quantum Hall set ups featuring
quantum point contacts. The approach developed here entails a phenomenological
description of spin resolved inter-edge scattering induced via hyperfine
assisted electron-nuclear spin flip-flop processes. A self-consistent
simulation framework between the nuclear spin dynamics and edge state
electronic transport is presented in order to gain crucial insights into the
dynamic nuclear polarization effects on electronic transport and in turn the
electron-spin polarization effects on the nuclear spin dynamics. In particular,
we show that the hysteresis noted experimentally in the conductance-voltage
trace as well as in the resistively detected NMR lineshape results from a lack
of quasi-equilibrium between electronic transport and nuclear polarization
evolution. In addition, we present circuit models to emulate such hyperfine
mediated transport effects to further facilitate a clear understanding of the
electronic transport processes occurring around the quantum point contact.
Finally, we extend our model to account for the effects of quadrupolar
splitting of nuclear levels and also depict the electronic transport signatures
that arise from single and multi-photon processes.Comment: 21 pages, 8 figure
High temperature glass coatings for superalloys and refractory metals
New glasses are used as protective coatings on metals and alloys susceptible to oxidation at high temperatures in oxidizing atmospheres. Glasses are stable and solid at temperatures up to 1000 deg C, adhere well to metal surfaces, and are usable for metals with broad range of expansion coefficients
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