41,853 research outputs found
The Effects of Rotation on the Evolution of Rising Omega-loops in a Stratified Model Convection Zone
We present three-dimensional MHD simulations of buoyant magnetic flux tubes
that rise through a stratified model convection zone in the presence of solar
rotation. The equations of MHD are solved in the anelastic approximation, and
the results are used to determine the effects of solar rotation on the dynamic
evolution an Omega-loop. We find that the Coriolis force significantly
suppresses the degree of fragmentation at the apex of the loop during its
ascent toward the photosphere. If the initial axial field strength of the tube
is reduced, then, in the absence of forces due to convective motions, the
degree of apex fragmentation is also reduced. We show that the Coriolis force
slows the rise of the tube, and induces a retrograde flow in both the
magnetized and unmagnetized plasma of an emerging active region.
Observationally, we predict that this flow will appear to originate at the
leading polarity, and will terminate at the trailing polarity.Comment: 25 pages, 8 figures, ApJ in pres
Distributions of gaps and end-to-end correlations in random transverse-field Ising spin chains
A previously introduced real space renormalization-group treatment of the
random transverse-field Ising spin chain is extended to provide detailed
information on the distribution of the energy gap and the end-to-end
correlation function for long chains with free boundary conditions. Numerical
data, using the mapping of the problem to free fermions, are found to be in
good agreement with the analytic finite size scaling predictions.Comment: 12 pages revtex, 10 figures, submitted to Phys. Rev.
Atypical energy eigenstates in the Hubbard chain and quantum disentangled liquids
We investigate the implications of integrability for the existence of quantum
disentangled liquid (QDL) states in the half-filled one-dimensional Hubbard
model. We argue that there exist finite energy-density eigenstates that exhibit
QDL behaviour in the sense of J. Stat. Mech. P10010 (2014). These states are
atypical in the sense that their entropy density is smaller than that of
thermal states at the same energy density. Furthermore, we show that thermal
states in a particular temperature window exhibit a weaker form of the QDL
property, in agreement with recent results obtained by strong-coupling
expansion methods in arXiv:1611.02075. This article is part of the themed issue
`Breakdown of ergodicity in quantum systems: from solids to synthetics matter'.Comment: 11 pages, 3 figures. arXiv admin note: text overlap with
arXiv:1611.0207
Current-voltage scaling of chiral and gauge-glass models of two-dimensional superconductors
The scaling behavior of the current-voltage characteristics of chiral and
gauge glass models of disordered superconductors, are studied numerically, in
two dimensions. For both models, the linear resistance is nonzero at finite
temperatures and the scaling analysis of the nonlinear resistivity is
consistent with a phase transition at T=0 temperature characterized by a
diverging correlation length and thermal critical
exponent . The values of , however, are found to be different
for the chiral and gauge glass models, suggesting different universality
classes, in contrast to the result obtained recently in three dimensions.Comment: 4 pages, 4 figures (included), to appear in Phys. Rev.
Active management of multi-service networks.
Future multiservice networks will be extremely large and complex. Novel management solutions will be required to keep the management costs reasonable. Active networking enables management to be delegated to network users as a large set of independent small scale management systems. A novel architecture for an active network based management solution for multiservice networking is presented
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