10,764 research outputs found
Ergodic property of Markovian semigroups on standard forms of von Neumann algebras
We give sufficient conditions for ergodicity of the Markovian semigroups
associated to Dirichlet forms on standard forms of von Neumann algebras
constructed by the method proposed in Refs. [Par1,Par2]. We apply our result to
show that the diffusion type Markovian semigroups for quantum spin systems are
ergodic in the region of high temperatures where the uniqueness of the
KMS-state holds.Comment: 25 page
Extensive divergence of transcription factor binding in Drosophila embryos with highly conserved gene expression
Extensive divergence of transcription factor binding in Drosophila embryos
with highly conserved gene expressionComment: 7 figures, 20 supplementary figures, 6 supplementary tables Paris M,
Kaplan T, Li XY, Villalta JE, Lott SE, et al. (2013) Extensive Divergence of
Transcription Factor Binding in Drosophila Embryos with Highly Conserved Gene
Expression. PLoS Genet 9(9): e1003748. doi:10.1371/journal.pgen.100374
Optimal routing on complex networks
We present a novel heuristic algorithm for routing optimization on complex
networks. Previously proposed routing optimization algorithms aim at avoiding
or reducing link overload. Our algorithm balances traffic on a network by
minimizing the maximum node betweenness with as little path lengthening as
possible, thus being useful in cases when networks are jamming due to queuing
overload. By using the resulting routing table, a network can sustain
significantly higher traffic without jamming than in the case of traditional
shortest path routing.Comment: 4 pages, 5 figure
Quantum tunneling on graphs
We explore the tunneling behavior of a quantum particle on a finite graph, in
the presence of an asymptotically large potential. Surprisingly the behavior is
governed by the local symmetry of the graph around the wells.Comment: 18 page
A_4 flavour symmetry breaking scheme for understanding quark and neutrino mixing angles
We propose a spontaneous A_4 flavour symmetry breaking scheme to understand
the observed pattern of quark and neutrino mixing. The fermion mass eigenvalues
are arbitrary, but the mixing angles are constrained in such a way that the
overall patterns are explained while also leaving sufficient freedom to fit the
detailed features of the observed values, including CP violating phases. The
scheme realises the proposal of Low and Volkas to generate zero quark mixing
and tribimaximal neutrino mixing at tree-level, with deviations from both
arising from small corrections after spontaneous A_4 breaking. In the neutrino
sector, the breaking is A_4 --> Z_2, while in the quark and charged-lepton
sectors it is A_4 --> Z_3 = C_3. The full theory has A_4 completely broken, but
the two different unbroken subgroups in the two sectors force the dominant
mixing patterns to be as stated above. Radiative effects within each sector are
shown to deviate neutrino mixing from tribimaximal, while maintaining zero
quark mixing. Interactions between the two sectors -- "cross-talk" -- induce
nonzero quark mixing, and additional deviation from tribimaximal neutrino
mixing. We discuss the vacuum alignment challenge the scenario faces, and
suggest three generic ways to approach the problem. We follow up one of those
ways by sketching how an explicit model realising the symmetry breaking
structure may be constructed.Comment: 14 pages, no figures; v3: Section 5 rewritten to correct an error;
new section added to the appendix; added references; v4: minor change to
appendix C, version to be published by JHE
Scaling for Interfacial Tensions near Critical Endpoints
Parametric scaling representations are obtained and studied for the
asymptotic behavior of interfacial tensions in the \textit{full} neighborhood
of a fluid (or Ising-type) critical endpoint, i.e., as a function \textit{both}
of temperature \textit{and} of density/order parameter \textit{or} chemical
potential/ordering field. Accurate \textit{nonclassical critical exponents} and
reliable estimates for the \textit{universal amplitude ratios} are included
naturally on the basis of the ``extended de Gennes-Fisher'' local-functional
theory. Serious defects in previous scaling treatments are rectified and
complete wetting behavior is represented; however, quantitatively small, but
unphysical residual nonanalyticities on the wetting side of the critical
isotherm are smoothed out ``manually.'' Comparisons with the limited available
observations are presented elsewhere but the theory invites new, searching
experiments and simulations, e.g., for the vapor-liquid interfacial tension on
the two sides of the critical endpoint isotherm for which an amplitude ratio
is predicted.Comment: 42 pages, 6 figures, to appear in Physical Review
Gravitational conundrum? Dynamical mass segregation versus disruption of binary stars in dense stellar systems
Upon their formation, dynamically cool (collapsing) star clusters will,
within only a few million years, achieve stellar mass segregation for stars
down to a few solar masses, simply because of gravitational two-body
encounters. Since binary systems are, on average, more massive than single
stars, one would expect them to also rapidly mass segregate dynamically.
Contrary to these expectations and based on high-resolution Hubble Space
Telescope observations, we show that the compact, 15-30 Myr-old Large
Magellanic Cloud cluster NGC 1818 exhibits tantalizing hints at the >= 2 sigma
level of significance (> 3 sigma if we assume a power-law secondary-to-primary
mass-ratio distribution) of an increasing fraction of F-star binary systems
(with combined masses of 1.3-1.6 Msun) with increasing distance from the
cluster center, specifically between the inner 10 to 20" (approximately
equivalent to the cluster's core and half-mass radii) and the outer 60 to 80".
If confirmed, this will offer support of the theoretically predicted but thus
far unobserved dynamical disruption processes of the significant population of
'soft' binary systems---with relatively low binding energies compared to the
kinetic energy of their stellar members---in star clusters, which we have
access to here by virtue of the cluster's unique combination of youth and high
stellar density.Comment: Accepted for publication in The Astrophysical Journal; 19 pages in
AASTeX format; 3 figure
Quantized spin Hall effect in Helium three-A and other p-wave paired Fermi systems
In this paper we propose the quantized spin Hall effect (SHE) in the vortex
state of a rotating p-wave paired Fermi system in an inhomogeneous magnetic
field and in a weak periodic potential. It is the three dimensional extension
of the spin Hall effect for a 3He-A superfluid film studied in Ref. [1]. It may
also be considered as a generalization of the 3D quantized charge Hall effect
of Bloch electrons in Ref. [2] to the spin transport. The A-phase of 3He or,
more generally, the p-wave paired phase of a cold Fermi atomic gas, under
suitable conditions should be a good candidate to observe the SHE, because the
system has a conserved spin current (with no spin-orbit couplings).Comment: 6 pages, revised version
A New Renormalization Scheme of Fermion Fields in Electroweak Standard Model
This paper has been withdrawn by the author,due a immature idea.Comment: 6 page
Simulation studies of permeation through two-dimensional ideal polymer networks
We study the diffusion process through an ideal polymer network, using
numerical methods. Polymers are modeled by random walks on the bonds of a
two-dimensional square lattice. Molecules occupy the lattice cells and may jump
to the nearest-neighbor cells, with probability determined by the occupation of
the bond separating the two cells. Subjected to a concentration gradient across
the system, a constant average current flows in the steady state. Its behavior
appears to be a non-trivial function of polymer length, mass density and
temperature, for which we offer qualitative explanations.Comment: 8 pages, 4 figure
- …