共查询到20条相似文献,搜索用时 15 毫秒
1.
Luis M. Gaggero-Sager E. R. Pujals O. Sotolongo-Costa 《Brazilian Journal of Physics》2011,41(4-6):297-303
We recapitulate results from the infinite ergodic theory that are relevant to the theory of non-extensive entropies. In particular, we recall that the Lyapunov exponent of the corresponding systems is zero and that the deviation between neighboring trajectories does not necessarily grow polynomially. Nonetheless, as we show, no single quantity can describe this subexponential growth, the generalized q-exponential exp q being, in particular, ruled out. We also revisit a number of dynamical systems preserving nonfinite ergodic measure. 相似文献
2.
Families of analytical solutions are found for symmetric and antisymmetric solitons in a dual-core system with Kerr nonlinearity and parity-time (PT)-balanced gain and loss. The crucial issue is stability of the solitons. A stability region is obtained in an analytical form, and verified by simulations, for the PT-symmetric solitons. For the antisymmetric ones, the stability border is found in a numerical form. Moving solitons of both types collide elastically. The two soliton species merge into one in the "supersymmetric" case, with equal coefficients of gain, loss, and intercore coupling. These solitons feature a subexponential instability, which may be suppressed by periodic switching ("management"). 相似文献
3.
Sisan DR Mujica N Tillotson WA Huang YM Dorland W Hassam AB Antonsen TM Lathrop DP 《Physical review letters》2004,93(11):114502
Differential rotation occurs in conducting flows in accretion disks and planetary cores. In such systems, the magnetorotational instability can arise from coupling Lorentz and centrifugal forces to cause large radial angular momentum fluxes. We present the first experimental observation of the magnetorotational instability. Our system consists of liquid sodium between differentially rotating spheres, with an imposed coaxial magnetic field. We characterize the observed patterns, dynamics, and torque increases, and establish that this instability can occur from a hydrodynamic turbulent background. 相似文献
4.
We study the continuous spin systems on ad3-dimensional lattice with random ferromagnetic interactions of finite range. We show that, if the temperature is sufficiently high and the probability of interaction to be large is small enough, the almost sure decay to equilibrium has a subexponential upper bound. 相似文献
5.
We have identified experimentally secondary instability mechanisms that restrict the stable band of wave numbers for ideal hexagons in Bénard-Marangoni convection. We use "thermal laser writing" to impose long wave perturbations of ideal hexagonal patterns as initial conditions and measure the growth rates of the perturbations. For epsilon=0.46 our results suggest a longitudinal phase instability limits stable hexagons at a high wave number while a transverse phase instability limits low wave number hexagons. 相似文献
6.
7.
Boguslaw Zegarlinski 《Journal of statistical physics》1994,77(3-4):717-732
We consider a spin system on a lattice with finite-range, possibly unbounded random interactions. We show that for such systems the Glauber dynamics cannot decay to equilibrium exponentially fast inL
2 even at high temperatures. Additionally, for one-dimensional systems with unbounded random couplings we prove that with probability one the corresponding Glauber dynamics has a fast (subexponential) decay to equilibrium in the uniform norm, provided that the distribution of random couplings satisfies some exponential bound. 相似文献
8.
The error rate in complementary transistor circuits is suppressed exponentially in electron number, arising from an intrinsic physical implementation of fault-tolerant error correction. Contrariwise, explicit assembly of gates into the most efficient known fault-tolerant architecture is characterized by a subexponential suppression of error rate with electron number, and incurs significant overhead in wiring and complexity. We conclude that it is more efficient to prevent logical errors with physical fault tolerance than to correct logical errors with fault-tolerant architecture. 相似文献
9.
Regensburger A Bersch C Hinrichs B Onishchukov G Schreiber A Silberhorn C Peschel U 《Physical review letters》2011,107(23):233902
We study light propagation in a photonic system that shows stepwise evolution in a discretized environment. It resembles a discrete-time version of photonic waveguide arrays or quantum walks. By introducing controlled photon losses to our experimental setup, we observe unexpected effects like subexponential energy decay and formation of complex fractal patterns. This demonstrates that the interplay of linear losses, discreteness and energy gradients leads to genuinely new coherent phenomena in classical and quantum optical experiments. Moreover, the influence of decoherence is investigated. 相似文献
10.
Oi DK 《Physical review letters》2003,91(6):067902
We show how interferometry can be used to characterize certain aspects of general quantum processes and, in particular, the coherence of completely positive maps. We derive a measure of coherent fidelity, the maximum interference visibility, and the closest unitary operator to a given physical process under this measure. 相似文献
11.
The resonant dynamics of mediated interactions supports zero sound in a cold atom degenerate mixture of a single-component fermion gas and a Bose-Einstein condensate. We characterize the onset of instability in the phase separation of an unstable mixture and we find a rich collective mode structure for stable mixtures with one undamped mode that exhibits an avoided crossing and a Landau-damped mode that terminates. 相似文献
12.
We studied the formation of χ disclination lines in planar cholesteric samples placed in a temperature gradient near the cholesteric
to smectic A phase transition. We observed that the first simple line which forms close to the smectic-cholesteric front zigzags
when it is perpendicular to the direction of planar anchoring and is straight for other orientations. This instability is
similar to Herring instability for crystalline surfaces. We show numerically that it originates from a strong increase of
the elastic anisotropy close to the transition. In addition, we propose a new method to measure the pitch divergence at the
smectic to cholesteric phase transition. 相似文献
13.
Using optical microscopy, phase shifting interferometry, and atomic force microscopy, we characterize the undulated structures which appear in the meniscus of freestanding ferroelectric smectic-C* films. We demonstrate that these periodic structures correspond to undulations of the smectic-air interface. The resulting striped pattern disappears in the untilted smectic-A phase. The modulation amplitude and wavelength of the instability both depend on meniscus thickness. We study the temperature evolution and propose a model that qualitatively accounts for the observations. 相似文献
14.
We comment on recently proposed dissipative inflationary models. It is shown that the strength of the inflationary expansion is related to a specific combination of thermodynamic variables which is known to measure the instability of self-gravitating dissipative systems. 相似文献
15.
We investigate the stability and instability of pathologies of renormalization group transformations for lattice spin systems under decimation. In particular we show that, even if the original renormalization group transformation gives rise to a non-Gibbsian measure, Gibbsianness may be restored by applying an extra decimation transformation. This fact is illustrated in detail for the block spin transformation applied to the Ising model. We also discuss the case of another non-Gibbsian measure with nicely decaying correlations functions which remains non-Gibbsian after arbitrary decimation. 相似文献
16.
D. Gomila P. Colet M. S. Miguel G.-L. Oppo 《The European physical journal. Special topics》2007,146(1):71-86
We discuss the relation between the dynamics of walls separating
two equivalent domains and the existence of different kinds of localized
structures in systems far from thermodynamic equilibrium. In particular we
focus in systems displaying a modulational instability of a flat front where an
amplitude equation for the dynamics of the curvature allows to characterize
different growth regimes and to predict the existence of stable droplets,
localized structures whose stability comes from nonlinear curvature effects. 相似文献
17.
We show that the "sputter patterning" topographical instability is determined by the effects of ion impact-induced prompt atomic redistribution and that erosion--the consensus predominant cause--is essentially irrelevant. We use grazing incidence small angle x-ray scattering to measure in situ the damping of noise or its amplification into patterns via the linear dispersion relation. A model based on the effects of impact-induced redistribution of those atoms that are not sputtered away explains both the observed ultrasmoothening at low angles from normal incidence and the instability at higher angles. 相似文献
18.
Markov chains are used to characterize a Dynamical system after it has reached the chaotic regime when certain external parameters have passed specific critical values. For a quantitative treatment of this stochastic behavior one needs an invariant measure. This measure then depends on the external parameters. We propose an emperical method to construct from first principles an invariant measure for the particular case of the triangular map. 相似文献
19.
We investigate the spatial modulation instability in colloidal suspension based on the nonlinear Schrödinger equation. By a standard linear stability analysis, we obtain the expression for instability gain and identified the relationship between the measurable instability characteristic parameters and the particle radius, the optical beam width. It is shown that the modulation growth rate, the maximum growth rate, cut-off frequency and the fastest growth frequency increase as the particle radius decreases and (or) the beam width increases if the optical intensity is constant. Moreover, the ultimate values of the cut-off frequency and the fastest growth frequency are proportional to the beam width, while are independent of the sphere radius. The results provide a new approach to measure the sphere radius and to control the characteristic parameters of modulation instability through the beam width. 相似文献
20.
Roberto Markarian 《Journal of statistical physics》1995,80(5-6):1207-1239
We prove statistical properties of two-dimensional hyperbolic dynamical systems with singularities. Bunimovich, Sinai, and Chernov proved a theorem on the subexponential decay of correlations and a central limit theorem for billiard systems. In this paper we use their techniques to prove the same results for abstract systems. 相似文献