56,987 research outputs found
Phase Synchronization and Polarization Ordering of Globally-Coupled Oscillators
We introduce a prototype model for globally-coupled oscillators in which each
element is given an oscillation frequency and a preferential oscillation
direction (polarization), both randomly distributed. We found two collective
transitions: to phase synchronization and to polarization ordering. Introducing
a global-phase and a polarization order parameters, we show that the transition
to global-phase synchrony is found when the coupling overcomes a critical value
and that polarization order enhancement can not take place before global-phase
synchrony. We develop a self-consistent theory to determine both order
parameters in good agreement with numerical results
Synchronization from Disordered Driving Forces in Arrays of Coupled Oscillators
The effects of disorder in external forces on the dynamical behavior of
coupled nonlinear oscillator networks are studied. When driven synchronously,
i.e., all driving forces have the same phase, the networks display chaotic
dynamics. We show that random phases in the driving forces result in regular,
periodic network behavior. Intermediate phase disorder can produce network
synchrony. Specifically, there is an optimal amount of phase disorder, which
can induce the highest level of synchrony. These results demonstrate that the
spatiotemporal structure of external influences can control chaos and lead to
synchronization in nonlinear systems.Comment: 4 pages, 4 figure
The Effect of Different Phases of Synchrony on Pain Threshold in a Drumming Task
Behavioral synchrony has been linked to endorphin activity (Cohen et al., 2010; Sullivan
and Rickers, 2013; Sullivan et al., 2014; Tarr et al., 2015, 2016; Weinstein et al., 2016).
This has been called the synchrony effect. Synchrony has two dominant phases of
movement; in-phase and anti-phase. The majority of research investigating synchrony’s
effect on endorphin activity has focused on in-phase synchrony following vigorous
activities. The only research to investigate the effects of anti-phase synchrony on
endorphin activity found that anti-phase synchronized rowing did not produce the
synchrony effect (Sullivan et al., 2014). Anti-phase synchrony, however, is counterintuitive
to the sport of rowing and may have interfered with the synchrony effect.
This study investigated the effect of anti-phase synchrony on endorphin activity in a
different task (i.e., drumming). University students (n D 30) were asked to drum solo
and in in-phase and anti-phase pairs for 3 min. Pain threshold was assessed as an
indirect indicator of endorphin activity prior to and following the task. Although the
in-phase synchrony effect was not found, a repeated measures ANOVA found that
there was a significant difference in pain threshold change among the three conditions
[F(2,24) D 4.10, !
N2 D 0.255, p < 0.05). Post hoc t-tests showed that the anti-phase
condition had a significantly greater pain threshold change than both the solo and
in-phase conditions at p < 0.05. This is the first time that anti-phase synchrony has
been shown to produce the synchrony effect. Because anti-phase drumming may have
required more attention between partners than in-phase synchrony, it may have affected
self-other merging (Tarr et al., 2014). These results support Tarr et al.’s (2014) model that
multiple mechanisms account for the effect of synchrony on pain threshold, and suggest
that different characteristics of the activity may influence the synchrony effect.Brock University Library Open Access Publishing Fun
Asynchronism Induces Second Order Phase Transitions in Elementary Cellular Automata
Cellular automata are widely used to model natural or artificial systems.
Classically they are run with perfect synchrony, i.e., the local rule is
applied to each cell at each time step. A possible modification of the updating
scheme consists in applying the rule with a fixed probability, called the
synchrony rate. For some particular rules, varying the synchrony rate
continuously produces a qualitative change in the behaviour of the cellular
automaton. We investigate the nature of this change of behaviour using
Monte-Carlo simulations. We show that this phenomenon is a second-order phase
transition, which we characterise more specifically as belonging to the
directed percolation or to the parity conservation universality classes studied
in statistical physics
Dynamics of coupled oscillator systems in presence of a local potential
We consider a long-range model of coupled phase-only oscillators subject to a
local potential and evolving in presence of thermal noise. The model is a
non-trivial generalization of the celebrated Kuramoto model of collective
synchronization. We demonstrate by exact results and numerics a surprisingly
rich long-time behavior, in which the system settles into either a stationary
state that could be in or out of equilibrium and supports either global
synchrony or absence of it, or, in a time-periodic synchronized state. The
system shows both continuous and discontinuous phase transitions, as well as an
interesting reentrant transition in which the system successively loses and
gains synchrony on steady increase of the relevant tuning parameter.Comment: v2: close to the published versio
- …