8,396 research outputs found
Cascades of Dynamical Transitions in an Adaptive Population
In an adaptive population which models financial markets and distributed
control, we consider how the dynamics depends on the diversity of the agents'
initial preferences of strategies. When the diversity decreases, more agents
tend to adapt their strategies together. This change in the environment results
in dynamical transitions from vanishing to non-vanishing step sizes. When the
diversity decreases further, we find a cascade of dynamical transitions for the
different signal dimensions, supported by good agreement between simulations
and theory. Besides, the signal of the largest step size at the steady state is
likely to be the initial signal.Comment: 4 pages, 8 figure
Experimental observation of negative differential resistance from an InAs/GaSb interface
We have observed negative differential resistance at room temperature from devices consisting of a single interface between n-type InAs and p-type GaSb. InAs and GaSb have a type II staggered band alignment; hence, the negative differential resistance arises from the same mechanism as in a p+-n+ tunnel diode. Room-temperature peak current densities of 8.2×10^4 A/cm^2 and 4.2×10^4 A/cm^2 were measured for structures with and without undoped spacer layers at the heterointerface, respectively
Perturbed Three Vortex Dynamics
It is well known that the dynamics of three point vortices moving in an ideal
fluid in the plane can be expressed in Hamiltonian form, where the resulting
equations of motion are completely integrable in the sense of Liouville and
Arnold. The focus of this investigation is on the persistence of regular
behavior (especially periodic motion) associated to completely integrable
systems for certain (admissible) kinds of Hamiltonian perturbations of the
three vortex system in a plane. After a brief survey of the dynamics of the
integrable planar three vortex system, it is shown that the admissible class of
perturbed systems is broad enough to include three vortices in a half-plane,
three coaxial slender vortex rings in three-space, and `restricted' four vortex
dynamics in a plane. Included are two basic categories of results for
admissible perturbations: (i) general theorems for the persistence of invariant
tori and periodic orbits using Kolmogorov-Arnold-Moser and Poincare-Birkhoff
type arguments; and (ii) more specific and quantitative conclusions of a
classical perturbation theory nature guaranteeing the existence of periodic
orbits of the perturbed system close to cycles of the unperturbed system, which
occur in abundance near centers. In addition, several numerical simulations are
provided to illustrate the validity of the theorems as well as indicating their
limitations as manifested by transitions to chaotic dynamics.Comment: 26 pages, 9 figures, submitted to the Journal of Mathematical Physic
Perturbation Calculation of the Axial Anomaly of a Ginsparg-Wilson lattice Dirac operator
A recent proposal suggests that even if a Ginsparg-Wilson lattice Dirac
operator does not possess any topological zero modes in
topologically-nontrivial gauge backgrounds, it can reproduce correct axial
anomaly for sufficiently smooth gauge configurations, provided that it is
exponentially-local, doublers-free, and has correct continuum behavior. In this
paper, we calculate the axial anomaly of this lattice Dirac operator in weak
coupling perturbation theory, and show that it recovers the topological charge
density in the continuum limit.Comment: 25 pages, v2: calculation up to O(g^4) for nonabelian gauge
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Two-body charmed baryon decays involving decuplet baryon in the quark-diagram scheme
In the quark-diagram scheme, we study the charmed baryon decays of , where is or ,
together with () the decuplet baryon (pseudoscalar meson). It is
found that only two -exchange processes are allowed to contribute to . Particularly, we predict , which respects the
isospin symmetry. Besides, we take into account the flavor symmetry
breaking, in order to explain the observation of . For the decays involving , we predict
as the largest branching fractions in
the singly Cabibbo-suppressed decay
channels, respectively, which are accessible to the LHCb, BELLEII and BESIII
experiments.Comment: 12 pages, 1 figure, 3 tables, version to appear in EPJ
Local tunneling spectroscopy as signatures of the Fulde-Ferrell-Larkin-Ovchinnikov state in s- and d-wave Superconductors
The Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) states for two-dimensional s- and
d-wave superconductors (s- and d-SC) are self-consistently studied under an
in-plane magnetic field. While the stripe solution of the order parameter (OP)
is found to have lower free energy in s-SC, a square lattice solution appears
to be energetically more favorable in the case of d-SC. At certain symmetric
sites, we find that the features in the local density of states (LDOS) can be
ascribed to two types of bound states. We also show that the LDOS maps for d-SC
exhibit bias-energy-dependent checkerboard patterns. These characteristics can
serve as signatures of the FFLO states.Comment: 5 pages, 5 figures Type and grammaratic errors corrected. Last figure
replaced by colored one. To appear in PR
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