291 research outputs found
Two Dimensional Quantum Chromodynamics on a Cylinder
We study two dimensional Quantum Chromodynamics with massive quarks on a
cylinder in a light--cone formalism. We eliminate the non--dynamical degrees of
freedom and express the theory in terms of the quark and Wilson loop variables.
It is possible to perform this reduction without gauge fixing. The fermionic
Fock space can be defined independent of the gauge field in this light--cone
formalism.Comment: 8 pages, UR-128
Correlation Functions of a Conformal Field Theory in Three Dimensions
We derive explicit forms of the two--point correlation functions of the
non-linear sigma model at the critical point, in the large limit, on
various three dimensional manifolds of constant curvature. The two--point
correlation function, , is the only -point correlation function
which survives in this limit. We analyze the short distance and long distance
behaviour of . It is shown that decays exponentially with
the Riemannian distance on the spaces . The decay on is of course a power law. We
show that the scale for the correlation length is given by the geometry of the
space and therefore the long distance behaviour of the critical correlation
function is not necessarily a power law even though the manifold is of infinite
extent in all directions; this is the case of the hyperbolic space where the
radius of curvature plays the role of a scale parameter. We also verify that
the scalar field in this theory is a primary field with weight ; we illustrate this using the example of the manifold
whose metric is conformally equivalent to that of up to a
reparametrization.Comment: 15 pages, Late
Studies on vibration of some rib-stiffened cantilever plates
The vibrational mode shapes and frequencies of rib-stiffened skew cantilever plates as determined by holographic interferometry are given. The effects of varying the sweep back angle, rib stiffness and aspect ratio are studied along with the influence of varying the boundary conditions at the root chord on the vibrational behavior of the plates. The study is applicable to investigating the vibrational behavior of stiffened plates often used in the design of guided rockets and missiles
Solvent-exposed tryptophans probe the dynamics at protein surfaces
The dynamics of single tryptophan (W) side chain of protease subtilisin Carlsberg (SC) and myelin basic protein (MBP) were used for probing the surface of these proteins. The W side chains are exposed to the solvent, as shown by the extent of quenching of their fluorescence by KI. Time-resolved fluorescence anisotropy measurements showed that the rotational motion of W is completely unhindered in the case of SC and partially hindered in the case of MBP. The rotational correlation time (Φ) associated with the fast local motion of W did not scale linearly with the bulk solvent viscosity (η) in glycerol-water mixtures. In contrast, Φ values of either W side chains in the denatured proteins or the free W scaled almost linearly with η, as expected by the Stokes-Einstein relationship. These results were interpreted as indicating specific partitioning of water at the surface of the proteins in glycerol-water mixtures
Disordered free fermions and the Cardy Ostlund fixed line at low temperature
Using functional RG, we reexamine the glass phase of the 2D random-field Sine
Gordon model. It is described by a line of fixed points (FP) with a
super-roughening amplitude as
temperature is varied. A speculation is that this line is identical to the
one found in disordered free-fermion models via exact results from ``nearly
conformal'' field theory. This however predicts , contradicting
numerics. We point out that this result may be related to failure of
dimensional reduction, and that a functional RG method incorporating higher
harmonics and non-analytic operators predicts a non-zero which
compares reasonably with numerics.Comment: 8 pages, 3 figures, only material adde
What do school children and teachers in rural Maharashtra think of AIDS and sex?
This paper discusses findings on issues related to sex and AIDS based on focus-group discussions conducted among students and teachers in the rural areas of Maharashtra. Most students were not sure whether AIDS could affect them, or how it could be contracted; some standard IX girl students stated the need for sex education at early ages. Most teachers did not want to talk about sex or student sexual behaviour; they stressed moral issues
High-temperature hardness of Ga_(1−x)In_xAs
Substantial solid‐solution strengthening of GaAs by In acting as InAs_4 units has recently been predicted for an intermediate‐temperature plateau region. This strengthening could account, in part, for the reduction of dislocation density in GaAs single crystals grown from the melt. Hardness measurements at high temperatures up to 900 °C have been carried out on (100) GaAs, Ga_(0.9975)In_(0.0025)As, and Ga_(0.99)In_(0.01)As wafers, all of which contain small amounts of boron. Results show a significant strengthening effect in In‐doped GaAs. A nominally temperature‐independent flow‐stress region is observed for all three alloys. The In‐doped GaAs shows a higher plateau stress level with increasing In content. The results are consistent with the solid‐solution strengthening model. The magnitude of the solid‐solution hardening is sufficient to explain the reduction in dislocation density with In addition
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