881 research outputs found
Synchrony breakdown and noise-induced oscillation death in ensembles of serially connected spin-torque oscillators
We consider collective dynamics in the ensemble of serially connected
spin-torque oscillators governed by the Landau-Lifshitz-Gilbert-Slonczewski
magnetization equation. Proximity to homoclinicity hampers synchronization of
spin-torque oscillators: when the synchronous ensemble experiences the
homoclinic bifurcation, the Floquet multiplier, responsible for the temporal
evolution of small deviations from the ensemble mean, diverges. Depending on
the configuration of the contour, sufficiently strong common noise, exemplified
by stochastic oscillations of the current through the circuit, may suppress
precession of the magnetic field for all oscillators. We derive the explicit
expression for the threshold amplitude of noise, enabling this suppression.Comment: 12 pages, 13 figure
The Power of the Past. Socio-Cultural Foundations of Retromania in Russia at the Turn of the Twentieth and the Twenty-First Centuries
This article defines and analyzes the phenomenon of retromania in the Russian cultural consciousness. The dominance of the past in the Russian collective consciousness is widely considered to have its roots in the Soviet experience of the twentieth century as part of the world historic experience of the age. In this study, its challenging, of-crisis-proportions semantic character is revealed; together with a material and spiritual-and-soulful weight that creates a strong magnetic pull, i.e. a kind of addiction for its bearers. With retromania, the ‘energy intensity’ of its substance, significance and burden, produced a deep although unconscious fatigue in the bearers of the experience – former Soviet people with a shared socio-cultural past. This is often transformed into a sense of impotence with regards to the present and the future, acting as an attribute and symptom of the fundamental anthropological crisis which is an integral outcome of the Soviet civilization. Finally, the dependence of retromania on both the nature of the Russian present and uncertainty of the future is shown.
Keywords: retromania, past, present, future, past historical experiences, its semantic, material and energy components, gravity pull of the Soviet experience and fundamental fatigue generated by it
Order-by-disorder in classical oscillator systems
We consider classical nonlinear oscillators on hexagonal lattices. When the
coupling between the elements is repulsive, we observe coexisting states, each
one with its own basin of attraction. These states differ by their degree of
synchronization and by patterns of phase-locked motion. When disorder is
introduced into the system by additive or multiplicative Gaussian noise, we
observe a non-monotonic dependence of the degree of order in the system as a
function of the noise intensity: intervals of noise intensity with low
synchronization between the oscillators alternate with intervals where more
oscillators are synchronized. In the latter case, noise induces a higher degree
of order in the sense of a larger number of nearly coinciding phases. This
order-by-disorder effect is reminiscent to the analogous phenomenon known from
spin systems. Surprisingly, this non-monotonic evolution of the degree of order
is found not only for a single interval of intermediate noise strength, but
repeatedly as a function of increasing noise intensity. We observe noise-driven
migration of oscillator phases in a rough potential landscape.Comment: 12 pages, 13 figures; comments are welcom
Steady Stokes flow with long-range correlations, fractal Fourier spectrum, and anomalous transport
We consider viscous two-dimensional steady flows of incompressible fluids
past doubly periodic arrays of solid obstacles. In a class of such flows, the
autocorrelations for the Lagrangian observables decay in accordance with the
power law, and the Fourier spectrum is neither discrete nor absolutely
continuous. We demonstrate that spreading of the droplet of tracers in such
flows is anomalously fast. Since the flow is equivalent to the integrable
Hamiltonian system with 1 degree of freedom, this provides an example of
integrable dynamics with long-range correlations, fractal power spectrum, and
anomalous transport properties.Comment: 4 pages, 4 figures, published in Physical Review Letter
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