2,718 research outputs found
The Abel-Zeilberger Algorithm
We use both Abel's lemma on summation by parts and Zeilberger's algorithm to
find recurrence relations for definite summations. The role of Abel's lemma can
be extended to the case of linear difference operators with polynomial
coefficients. This approach can be used to verify and discover identities
involving harmonic numbers and derangement numbers. As examples, we use the
Abel-Zeilberger algorithm to prove the Paule-Schneider identities, the
Apery-Schmidt-Strehl identity, Calkin's identity and some identities involving
Fibonacci numbers.Comment: 18 page
Predictive protocol of flocks with small-world connection pattern
By introducing a predictive mechanism with small-world connections, we
propose a new motion protocol for self-driven flocks. The small-world
connections are implemented by randomly adding long-range interactions from the
leader to a few distant agents, namely pseudo-leaders. The leader can directly
affect the pseudo-leaders, thereby influencing all the other agents through
them efficiently. Moreover, these pseudo-leaders are able to predict the
leader's motion several steps ahead and use this information in decision making
towards coherent flocking with more stable formation. It is shown that drastic
improvement can be achieved in terms of both the consensus performance and the
communication cost. From the industrial engineering point of view, the current
protocol allows for a significant improvement in the cohesion and rigidity of
the formation at a fairly low cost of adding a few long-range links embedded
with predictive capabilities. Significantly, this work uncovers an important
feature of flocks that predictive capability and long-range links can
compensate for the insufficiency of each other. These conclusions are valid for
both the attractive/repulsive swarm model and the Vicsek model.Comment: 10 pages, 12 figure
Study the Heavy Molecular States in Quark Model with Meson Exchange Interaction
Some charmonium-like resonances such as X(3872) can be interpreted as
possible molecular states. Within the quark model, we study
the structure of such molecular states and the similar
molecular states by taking into account of the light meson exchange (,
, , and ) between two light quarks from different
mesons
Fluctuation and localization of the nonlinear Hall effect on a disordered lattice
The nonlinear Hall effect has recently attracted significant interest due to
its potentials as a promising spectral tool and device applications. A theory
of the nonlinear Hall effect on a disordered lattice is a crucial step towards
explorations in realistic devices, but has not been addressed. We study the
nonlinear Hall response on a lattice, which allows us to introduce disorder
numerically and reveal a mechanism that was not discovered in the previous
momentum-space theories. In the mechanism, disorder induces an increasing
fluctuation of the nonlinear Hall conductance as the Fermi energy moves from
the band edges to higher energies. This fluctuation is a surprise, because it
is opposite to the disorder-free distribution of the Berry curvature. More
importantly, the fluctuation may explain those unexpected observations in the
recent experiments. We also discover an "Anderson localization" of the
nonlinear Hall effect. This work shows an emergent territory of the nonlinear
Hall effect yet to be explored
KN and KbarN Elastic Scattering in the Quark Potential Model
The KN and KbarN low-energy elastic scattering is consistently studied in the
framework of the QCD-inspired quark potential model. The model is composed of
the t-channel one-gluon exchange potential, the s-channel one-gluon exchange
potential and the harmonic oscillator confinement potential. By means of the
resonating group method, nonlocal effective interaction potentials for the KN
and KbarN systems are derived and used to calculate the KN and KbarN elastic
scattering phase shifts. By considering the effect of QCD renormalization, the
contribution of the color octet of the clusters (qqbar) and (qqq) and the
suppression of the spin-orbital coupling, the numerical results are in fairly
good agreement with the experimental data.Comment: 20 pages, 8 figure
An SO(10) GUT Model with Flavor Symmetry
We present a supersymmetric grand unification model based on SO(10) group
with flavor symmetry. In this model, the fermion masses are from Yukawa
couplings involving and Higgs multiplets and the
flavor structures of mass matrices of both quarks and leptons are determined by
spontaneously broken . This model fits all of the masses and mixing angles
of the quarks and leptons. For the most general CP-violation scenario, this
model gives a wide range of values from zero to the current
bound with the most probable values . With certain assumptions where
leptonic phases have same CP-violation source as CKM phase, one gets a narrower
range for with the most probable values
. This model gives leptonic Dirac CP phase the most probable values
2-4 radians in the general CP-violation case.Comment: 14 pages,2 figures. Version published in Physical Review
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