2,060 research outputs found
O(\alpha_s) Corrections to Longitudinal Spin-Spin Correlations in e+e- -> q qbar
We calculate the corrections to longitudinal spin-spin
correlations in . For top quark pair production the
corrections to the longitudinal spin-spin asymmetry amount to
less than 1% in the -range from above -treshold up to
. In the case the
corrections reduce the asymmetry value from its value of -1 to
approximately -0.96 for -values around the Z-peak. This reduction can be
traced to finite anomalous contributions from residual mass effects which
survive the limit. We discuss the role of the anomalous contributions
and the pattern of how they contribute to spin-flip and no-flip terms.Comment: 10 pages, 2 postscript figure
Relay synchronization in multiplex networks
Relay (or remote) synchronization between two not directly connected
oscillators in a network is an important feature allowing distant coordination.
In this work, we report a systematic study of this phenomenon in multiplex
networks, where inter-layer synchronization occurs between distant layers
mediated by a relay layer that acts as a transmitter. We show that this
transmission can be extended to higher order relay configurations, provided
symmetry conditions are preserved. By first order perturbative analysis, we
identify the dynamical and topological dependencies of relay synchronization in
a multiplex. We find that the relay synchronization threshold is considerably
reduced in a multiplex configuration, and that such synchronous state is mostly
supported by the lower degree nodes of the outer layers, while hubs can be
de-multiplexed without affecting overall coherence. Finally, we experimentally
validated the analytical and numerical findings by means of a multiplex of
three layers of electronic circuits.the analytical and numerical findings by
means of a multiplex of three layers of electronic circuits
Synchronization interfaces and overlapping communities in complex networks
We show that a complex network of phase oscillators may display interfaces
between domains (clusters) of synchronized oscillations. The emergence and
dynamics of these interfaces are studied in the general framework of
interacting phase oscillators composed of either dynamical domains (influenced
by different forcing processes), or structural domains (modular networks). The
obtained results allow to give a functional definition of overlapping
structures in modular networks, and suggest a practical method to identify
them. As a result, our algorithm could detect information on both single
overlapping nodes and overlapping clusters.Comment: 5 pages, 4 figure
Explosive first-order transition to synchrony in networked chaotic oscillators
Critical phenomena in complex networks, and the emergence of dynamical abrupt
transitions in the macroscopic state of the system are currently a subject of
the outmost interest. We report evidence of an explosive phase synchronization
in networks of chaotic units. Namely, by means of both extensive simulations of
networks made up of chaotic units, and validation with an experiment of
electronic circuits in a star configuration, we demonstrate the existence of a
first order transition towards synchronization of the phases of the networked
units. Our findings constitute the first prove of this kind of synchronization
in practice, thus opening the path to its use in real-world applications.Comment: Phys. Rev. Lett. in pres
Abrupt field-induced transition triggered by magnetocaloric effect in phase-separated manganites
The occurrence at low temperatures of an ultrasharp field-induced transition
in phase separated manganites is analyzed. Experimental results show that
magnetization and specific heat step-like transitions below 5 K are correlated
with an abrupt change of the sample temperature, which happens at a certain
critical field. This temperature rise, a magnetocaloric effect, is interpreted
as produced by the released energy at the transition point, and is the key to
understand the existence of the abrupt field-induced transition. A qualitative
analysis of the results suggests the existence of a critical growing rate of
the ferromagnetic phase, beyond which an avalanche effect is triggered.Comment: 6 pages, 4 figures included. Acepted for publication in Phys. Rev.
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