Current-mediated synchronization of a pair of beating non-identical flagella

The basic phenomenology of experimentally observed synchronization (i.e., a stochastic phase locking) of identical, beating flagella of a biflagellate alga is known to be captured well by a minimal model describing the dynamics of coupled, limit-cycle, noisy oscillators (known as the noisy Kuramoto model). As demonstrated experimentally, the amplitudes of the noise terms therein, which stem from fluctuations of the rotary motors, depend on the flagella length. Here we address the conceptually important question which kind of synchrony occurs if the two flagella have different lengths such that the noises acting on each of them have different amplitudes. On the basis of a minimal model, too, we show that a different kind of synchrony emerges, and here it is mediated by a current carrying, steady-state; it manifests itself via correlated "drifts" of phases. We quantify such a synchronization mechanism in terms of appropriate order parameters $Q$ and $Q_{\cal S}$ - for an ensemble of trajectories and for a single realization of noises of duration ${\cal S}$, respectively. Via numerical simulations we show that both approaches become identical for long observation times ${\cal S}$. This reveals an ergodic behavior and implies that a single-realization order parameter $Q_{\cal S}$ is suitable for experimental analysis for which ensemble averaging is not always possible.Comment: 10 pages, 2 figure

Cooperative behavior of qutrits with dipole-dipole interactions

We have identified a class of many body problems with analytic solution beyond the mean-field approximation. This is the case where each body can be considered as an element of an assembly of interacting particles that are translationally frozen multi-level quantum systems and that do not change significantly their initial quantum states during the evolution. In contrast, the entangled collective state of the assembly experiences an appreciable change. We apply this approach to interacting three-level systems.Comment: 5 pages, 3 figures. Minor correction

Effect of ultrasonic treatment on the X-band microwave absorption of multiwalled carbon nanocomposite

This paper presents results of calculation reflection coefficients multiwalled carbon nanotubes (MWCNTs)-laquer composites at microwave frequencies. Two groups of composite samples with 1.0% weight percentages of MWCNTs were fabricated and tested. The multiwall carbon nanotubes used in the composite were about 18.6 nm and 9.4 nm in diameter. As a result, it is shown that the use different morphology MWCNTs entered in the making of composite material and various ultrasonic treatment times provide the change both absorption region width and absorption peak depth

Critical region of the random bond Ising model

We describe results of the cluster algorithm Special Purpose Processor simulations of the 2D Ising model with impurity bonds. Use of large lattices, with the number of spins up to $10^6$, permitted to define critical region of temperatures, where both finite size corrections and corrections to scaling are small. High accuracy data unambiguously show increase of magnetization and magnetic susceptibility effective exponents $\beta$ and $\gamma$, caused by impurities. The $M$ and $\chi$ singularities became more sharp, while the specific heat singularity is smoothed. The specific heat is found to be in a good agreement with Dotsenko-Dotsenko theoretical predictions in the whole critical range of temperatures.Comment: 11 pages, 16 figures (674 KB) by request to authors: [email protected] or [email protected], LITP-94/CP-0

On Vertex Operator Construction of Quantum Affine Algebras

We describe the construction of the quantum deformed affine Lie algebras using the vertex operators in the free field theory. We prove the Serre relations for the quantum deformed Borel subalgebras of affine algebras, namely the case of $\hat{\it sl}_{2}$ is considered in detail. We provide some formulas for generators of affine algebra.Comment: LaTeX, 9 pages; typos corrected, references adde

Influence of ultrasonic treatment on electromagnetic characteristics of composites based on multiwall carbon nanotubes at wide range of frequencies (100 Hz - 258 GHz)

In the present paper, we investigated microwave properties of polymer composites based on multiwall carbon nanotubes. The multiwall carbon nanotubes used in the composite were about 9.4 nm and 18.4 nm in diameter. The results show that the ultrasonic treatment modifies the dielectric properties of the composite. The dependence of the real and imaginary parts of the permittivity of sonication time is non linear. The results showed that composite material based on nanotubes with a diameter of 9.4 nm has a dispersive region of dielectric permittivity at the range about 10 GHz

Electromagnetic properties of texture composite materials based on hexagonal ferrites/multiwalled carbon nanotubes

In this article, the frequency dependence of the absorption coefficient and electromagnetic losses of the composite based on ferrite powder and / or multi-walled carbon nanotubes are presented. The dielectric and magnetic losses in the composite were measured in the range of 0.01 - 20 GHz. It has been found to increase the absorption of electromagnetic radiation and increased losses in the samples containing multi-walled carbon nanotubes

Effect of localized holes on the long-range order in bilayer antiferromagnets

The effect of localized holes on the long-range antiferromagnetic order in bilayer cuprates is studied, by applying the renormalization group to the appropriate non-linear sigma model. The theory accounts quantitatively for the magnetic phase diagram of Ca doepd YBa_2Cu_3O_6.Comment: 2 pages, to appear in Physica

Numerical study on Schramm-Loewner Evolution in nonminimal conformal field theories

The Schramm-Loewner evolution (SLE) is a powerful tool to describe fractal interfaces in 2D critical statistical systems. Yet the application of SLE is well established for statistical systems described by quantum field theories satisfying only conformal invariance, the so called minimal conformal field theories (CFTs). We consider interfaces in Z(N) spin models at their self-dual critical point for N=4 and N=5. These lattice models are described in the continuum limit by non-minimal CFTs where the role of a Z_N symmetry, in addition to the conformal one, should be taken into account. We provide numerical results on the fractal dimension of the interfaces which are SLE candidates for non-minimal CFTs. Our results are in excellent agreement with some recent theoretical predictions.Comment: 4 pages, 2 figures, v2: typos corrected, published versio