9,615 research outputs found
Characteristics of optical multi-peak solitons induced by higher-order effects in an erbium-doped fiber system
We study multi-peak solitons \textit{on a plane-wave background} in an
erbium-doped fiber system with some higher-order effects, which is governed by
a coupled Hirota and Maxwel-Bloch (H-MB) model. The important characteristics
of multi-peak solitons induced by the higher-order effects, such as the
velocity changes, localization or periodicity attenuation, and state
transitions, are revealed in detail. In particular, our results demonstrate
explicitly that a multi-peak soliton can be converted to an anti-dark soliton
when the periodicity vanishes; on the other hand, a multi-peak soliton is
transformed to a periodic wave when the localization vanishes. Numerical
simulations are performed to confirm the propagation stability of multi-peak
solitons riding on a plane-wave background. Finally, we compare and discuss the
similarity and difference of multi-peak solitons in special degenerate cases of
the H-MB system with general existence conditions.Comment: 7 pages, 4 figure
Strangeness hyperon-nucleon scattering in covariant chiral effective field theory
Motivated by the successes of covariant baryon chiral perturbation theory in
one-baryon systems and in heavy-light systems, we study relevance of
relativistic effects in hyperon-nucleon interactions with strangeness .
In this exploratory work, we follow the covariant framework developed by
Epelbaum and Gegelia to calculate the scattering amplitude at leading
order. By fitting the five low-energy constants to the experimental data, we
find that the cutoff dependence is mitigated, compared with the heavy-baryon
approach. Nevertheless, the description of the experimental data remains
quantitatively similar at leading order.Comment: The manuscript has been largely rewritten but the results remain
unchanged. To appear in Physical Review
Designing Fully Distributed Consensus Protocols for Linear Multi-agent Systems with Directed Graphs
This paper addresses the distributed consensus protocol design problem for
multi-agent systems with general linear dynamics and directed communication
graphs. Existing works usually design consensus protocols using the smallest
real part of the nonzero eigenvalues of the Laplacian matrix associated with
the communication graph, which however is global information. In this paper,
based on only the agent dynamics and the relative states of neighboring agents,
a distributed adaptive consensus protocol is designed to achieve
leader-follower consensus for any communication graph containing a directed
spanning tree with the leader as the root node. The proposed adaptive protocol
is independent of any global information of the communication graph and thereby
is fully distributed. Extensions to the case with multiple leaders are further
studied.Comment: 16 page, 3 figures. To appear in IEEE Transactions on Automatic
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