3,606,415 research outputs found
Bulk asymptotics of skew-orthogonal polynomials for quartic double well potential and universality in the matrix model
We derive bulk asymptotics of skew-orthogonal polynomials (sop)
\pi^{\bt}_{m}, , 4, defined w.r.t. the weight , , and . We assume that as there
exists an , such that , where is the critical value which separates
sop with two cuts from those with one cut. Simultaneously we derive asymptotics
for the recursive coefficients of skew-orthogonal polynomials. The proof is
based on obtaining a finite term recursion relation between sop and orthogonal
polynomials (op) and using asymptotic results of op derived in \cite{bleher}.
Finally, we apply these asymptotic results of sop and their recursion
coefficients in the generalized Christoffel-Darboux formula (GCD) \cite{ghosh3}
to obtain level densities and sine-kernels in the bulk of the spectrum for
orthogonal and symplectic ensembles of random matrices.Comment: 6 page
The energy level structure of a variety of one-dimensional confining potentials and the effects of a local singular perturbation
Motivated by current interest in quantum confinement potentials, especially
with respect to the Stark spectroscopy of new types of quantum wells, we
examine several novel one-dimensional singular oscillators. A Green function
method is applied, the construction of the necessary resolvents is reviewed and
several new ones are introduced. In addition, previous work on the singular
harmonic oscillator model, introduced by Avakian et al. is reproduced to verify
the method and results. A novel features is the determination of the spectra of
asymmetric hybrid linear and quadratic potentials. As in previous work, the
singular perturbations are modeled by delta functions.Comment: 14 pages, 10 figure
Chemo-capillary instabilities of a contact line
Equilibrium and motion of a contact line are viewed as analogs of phase
equilibrium and motion of an interphase boundary. This point of view makes
evident the tendency to minimization of the length of the contact line at
equilibrium. The concept of line tension is, however, of limited applicability,
in view of a qualitatively different relaxation response of the contact line,
compared to a two-dimensional curve. Both the analogy and qualitative
distinction extend to a non-equilibrium situation arising due to coupling with
reversible substrate modification. Under these conditions, the contact line may
suffer a variety of chemo-capillary instabilities (fingering, traveling and
oscillatory), similar to those of dissipative structures in nonlinear
non-equilibrium systems. The preference order of the various instabilities
changes, however, significantly due to a different way the interfacial
curvature is relaxed.Comment: 8 pages, 4 figures; corrected version of the published pape
Feasibility Analyses of Integrated Broiler Production
The major obstacles in the development of broiler raising is the expensive price of feed and the fluctuative price of DOCs. The cheap price of imported leg quarters reduces the competitiveness of the local broilers. Therefore, an effort to increase production efficiency is needed through integration between broiler raising and corn farmers and feed producers (integrated farming). The purpose of this study is to analyze the feasibility of integrating broiler raising with corn cultivation and feed production. Besides that, a simulation was conducted to analyze the effects of DOC price changes, broiler price and production capacity. The analyses showed that integrated farming and a mere combination between broiler raising and feed factory of a 10,000 bird capacity is not financially feasible. Increasing the production to 25,000 broiler chickens will make the integrated farming financially feasible. Unintegrated broiler raising is relatively sensitive to broiler price decreases and DOC price increases compared to integrated farming
Momentum spectra of charmonium produced in a quark-gluon plasma
We calculate rapidity and transverse momentum distributions of charmonium
formed in high energy heavy ion collsions from incoherent recombination of
charm quarks. The results are very sensitive to the corresponding distributions
of the charm quarks, and thus can serve as a probe of the state of matter
produced in the heavy ion collision. At one extreme we generate a set of charm
pair momenta directly from pQCD amplitudes, which are appropriate if one can
neglect interaction of the quarks with the medium. At the other extreme we
generate momenta of charm quarks in thermal equilibrium with the expanding
medium, appropriate for an extremely strong interaction. Explicit predictions
are made for J/Psi formation in Au-Au interactions at RHIC. We find that for
the case in which charm quark momenta are unchanged from the pQCD production
calculation, both the rapidity and transverse momentum spectra of the formed
J/Psi are substantially narrower than would be anticipated in scenarios which
do not include the in-medium formation. In particular, the average transverse
momentum of the J/Psi will exhibit a non-monotonic behavior in the progression
from p-p to p-A to A-A interactions.Comment: Final published version, clarifying remarks adde
Noise enhanced spontaneous chaos in semiconductor superlattices at room temperature
Physical systems exhibiting fast spontaneous chaotic oscillations are used to
generate high-quality true random sequences in random number generators. The
concept of using fast practical entropy sources to produce true random
sequences is crucial to make storage and transfer of data more secure at very
high speeds. While the first high-speed devices were chaotic semiconductor
lasers, the discovery of spontaneous chaos in semiconductor superlattices at
room temperature provides a valuable nanotechnology alternative. Spontaneous
chaos was observed in 1996 experiments at temperatures below liquid nitrogen.
Here we show spontaneous chaos at room temperature appears in idealized
superlattices for voltage ranges where sharp transitions between different
oscillation modes occur. Internal and external noises broaden these voltage
ranges and enhance the sensitivity to initial conditions in the superlattice
snail-shaped chaotic attractor thereby rendering spontaneous chaos more robust.Comment: 6 pages, 4 figures, revte
Matrices coupled in a chain. I. Eigenvalue correlations
The general correlation function for the eigenvalues of complex hermitian
matrices coupled in a chain is given as a single determinant. For this we use a
slight generalization of a theorem of Dyson.Comment: ftex eynmeh.tex, 2 files, 8 pages Submitted to: J. Phys.
Solar differential rotation and meridional flow: The role of a subadiabatic tachocline for the Taylor-Proudman balance
We present a simple model for the solar differential rotation and meridional
circulation based on a mean field parameterization of the Reynolds stresses
that drive the differential rotation. We include the subadiabatic part of the
tachocline and show that this, in conjunction with turbulent heat conductivity
within the convection zone and overshoot region, provides the key physics to
break the Taylor-Proudman constraint, which dictates differential rotation with
contour lines parallel to the axis of rotation in case of an isentropic
stratification. We show that differential rotation with contour lines inclined
by 10 - 30 degrees with respect to the axis of rotation is a robust result of
the model, which does not depend on the details of the Reynolds stress and the
assumed viscosity, as long as the Reynolds stress transports angular momentum
toward the equator. The meridional flow is more sensitive with respect to the
details of the assumed Reynolds stress, but a flow cell, equatorward at the
base of the convection zone and poleward in the upper half of the convection
zone, is the preferred flow pattern.Comment: 15 pages, 7 figure
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