Dynamics of an Orientational-Kink Pair in a Hydrogen-Bonded Chain in an External Field

We discuss dynamic properties of an orientational-kink pair in hydrogen-bonded chains in the presence of an external force and damping, based on a new two-component soliton model. We study the scattering of an electromagnetic wave by an orientational-kink pair. Finally, we find the expressions of the scattering cross-section of an orientational-kink pair for an electromagnetic wave and the mobility of the orientational-kink pair.     

Movement in an axial symmetric wave propagating in the solid state plasma in external fields

It is shown that an analog of Thomson waves, existing in an ideal fluid, is possible in metals and semiconductors. Possibility of observation of such waves is discussed.     

Limitation of network inhomogeneity in improving cooperation in coevolutionary dynamics

Cooperative behavior is common in nature even if selfishness is sometimes better for an individual. Empirical and theoretical studies have shown that the invasion and expansion of cooperators are related to an inhomogeneous connectivity distribution. Here we study the evolution of cooperation on an adaptive network, in which an individual is able to avoid being exploited by rewiring its link(s). Our results indicate that the broadening of connectivity distribution is not always beneficial for cooperation. Compared with the Poisson-like degree distribution, the exponential-like degree distribution is detrimental to the occurrence of a higher level of cooperation in the continuous snowdrift game (CSG).     

Electromagnetic propagation at interfaces and in waveguides in uniaxial crystals

The use of surface-impedance and surface-admittance concepts for analyzing reflection and refraction at an isotropic dielectric interface (first developed about 1938) is extended to include an interface between uniaxial birefringent dielectrics. Total internal reflection and the polarizing (Brewster) angle at an anisotropic interface are shown to be naturally explainable in terms of surface impedance (for TM polarization) and surface admittance (for TE polarization). The allowable modes in an integrated optical uniaxial asymmetric dielectric slab waveguide are also shown to be directly obtainable using the surface impedance/admittance approach. Numerical examples are presented.     

Conduction electron effective-mass in a field of excitons in semiconductors

The interaction of an electron with excitations of an exciton gas in a semi-conductor is considered in the intermediate coupling theory, to explain the recently observed enhancement of the electron effective mass in germanium in a field of real excitons.     

The use of ultrasound in the South Cone region. Advances in organic and inorganic synthesis and in analytical methods

In organic and inorganic synthesis and in analytical methods, an external conventional heat source is usually applied to carry out a chemical reaction at a high temperature, or an extraction procedure. In the last decades, the use of ultrasound as an alternative energy source has become an interesting field of research in these topics in the South Cone region (Argentina, Chile, Uruguay, Southern Brazil and Paraguay). For this reason, the present review, covering the period 2009 to mid-2021, is a compilation of ultrasound-assisted synthetic and analytical methodologies.     

Magnetoelectric properties in A-type antiferromagnet in an electric field

Mean-field theory based on Heisenberg model is used to investigate the magnetic and magnetoelectric properties at a finite temperature in the A-type antiferromagnetic lattice, in which we consider that an applied electric field can generate a bulk magnetic moment. We have calculated the magnetic moment, magnetic susceptibility and magnetoelectric susceptibility as a function of temperature for A-type antiferromagnetic system. It is demonstrated that an applied electric field together with the coupling parameter has an effect on the magnetic ordering behavior. Our results are almost consistent with those of spin-wave theory within the range of low temperature.     

Rectification in Luttinger liquids

We investigate the rectification of an ac bias in Luttinger liquids in the presence of an asymmetric potential (the ratchet effect). We show that a strong repulsive electron interaction enhances the ratchet current in comparison with Fermi-liquid systems, and the dc I-V curve is strongly asymmetric in the low-voltage regime even for a weak asymmetric potential. At higher voltages the ratchet current exhibits an oscillatory voltage dependence.     

Quantum chaotic scattering in atomic physics: Ericson fluctuations in photoionization

We report the first experimental investigation of quantum chaotic scattering in an atomic system: in strong crossed magnetic and electric fields in an energy regime beyond the ionization threshold, where the classical dynamics is an example of chaotic scattering. We find Ericson fluctuations in the spectra for photo excitation into this regime. This result constitutes the first observation of Ericson fluctuations in atomic and molecular physics. Furthermore, we confirm the prediction that chaotic scattering in the underlying classical dynamics implies Ericson fluctuations.     

Solvation forces in fluids

Using a formalism derived by us in an earlier paper we obtain the density profile and solvation force between two identical hard plates separated by a fluid characterized by (i) an Orstein-Zernike correlation function and (ii) a Percus-Yevick sticky sphere correlation function. Example (i) yields an exponential or hyperbolic density profile characterized by a correlation length ξ that diverges at the critical point as (T-T_c )^-v . The corresponding force is weak and attractive following an exponential law at large separations. Example (ii) yields an attractive force in the vicinity of the critical region and an oscillatory force at higher densities and/or higher temperatures which can significantly modify forces between colloid particles.     

Spin-orbital phase synchronization in the magnetic field-driven electron dynamics in a double-well potential

We study the dynamics of an electron confined in a one-dimensional double-well potential in the presence of driving external magnetic fields. The orbital motion of the electron is coupled to the spin dynamics by spin-orbit interaction of the Dresselhaus type. We derive an effective time-dependent model Hamiltonian for the orbital motion of the electron and obtain a condition for synchronization of the orbital and the spin dynamics. We find an analytical expression for the Arnold 'tongue' and propose an experimental scheme for realizing the proposed synchronization.     

Photon echo in an atomic frequency comb in a Pr-doped LaF3 crystal

The possibility of storage of an optical pulse in a memory based on an atomic frequency comb in a Pr³⁺:LaF₃ crystal is demonstrated experimentally. A new method of storage-time control using an external electric field is proposed and experimentally implemented.     

Employment of the scattering amplitude in solving the diffraction problems for waves in a halfspace

The problem on the diffraction of an acoustic wave by a finite-size scatterer (inclusion) located in a halfspace is considered. The method of solving this problem is based on the use of the scattering amplitude of the inclusion. A formula analogous to the Green formula is presented. It allows one to determine the scattering amplitude of the inclusion for an arbitrary incident wave (determined by the directional pattern of the source of primary waves) from the scattering amplitude corresponding to plane incident waves. The algorithm is presented for solving the problem on the operation of an acoustically opaque radiator in a halfspace whose boundary is characterized by an arbitrary reflection coefficient. As an example, the problem is solved on the generation of low-frequency oscillations by a sphere with an acoustically soft boundary near an acoustically hard or soft boundary of the halfspace.     

Relaxation in an entangled thermostat

A generalized Lindblad equation is derived that describes the relaxation of two systems of an arbitrary physical nature in an entangled thermostat. The relaxation of an atom and a mode of the electromagnetic field selected by a high-Q cavity is considered as an example. Using the introduced collective operators for an atom and a mode, it is shown that the entangled state of the thermostat can lead to the coherent and squeezed state of the atom and the mode.     

Vacancy pairs in sodalite

Sensitized sodalite is thought to contain paired anion and cation vacancies in the interstices of the alumino-silicate framework. Using an extension of the Born model to describe the potential in an interstice, the equilibrium configuration of a vacancy pair is calculated and the similarity between the anion site in the alkali halides and sodalite is discussed. The vacancy pair is shown to possess an electric dipole moment; hence it should exhibit dielectric loss.     

Anisotropy of Isobaric Instability in a Partially Ionized Plasma in a Magnetic Field

Bulletin of the Lebedev Physics Institute - Linear equations describing the dynamics of small perturbations in partially ionized heat-releasing plasma in an external magnetic field with an...     

Hybrid Optoelectronic Bistability in Frequency-Domain and Its Potential Application in FBG Sensors

We propose a novel optical bistable device （OBD） in frequency-domain with which we can perform optical bistable operations in a number of fibre Bragg gratings （FBGs） which are included in the same OBD. Such an OBD may bring more opportunities in applications and, as an example, we show the possibility of using it in an FBG sensor demodulating system. By use of a tunable light source, consisting of a broad band source and a scanning fibre F-P （FFP）, we demonstrate the above-mentioned operations experimentally.     

Beam propagation in elliptical fibres

We apply an operator method, based on the scalar wave equation, to study the propagation of a Gaussian light beam in an optical fibre with an arbitrary, elliptically symmetric refractive-index profile. We discover that ray optical results, while not capable of predicting the rapid distortion of an optical beam in a non-ideal refractive-index profile, successfully simulate the general form of the optical power distributions, even in non-ideal profiles. We find that the propagation patterns for elliptical fibres with and without a strongly scattering central index dip show several unexpected similarities.     

Self-Diffusion in Cell Membranes in the Long Time Regime

We consider the process of self-diffusion in the cellular structure in the presence of permeable barriers in long time regime. Based on the most general concepts of the translation mobility and geometry of a heterogeneous system, an expression for the self-diffusion coefficient of liquid molecules in such a medium in a long time regime was derived. We have shown that the value of the self-diffusion coefficient in the long-time limit is determined by the probability of interaction of the diffusant molecule with an obstacle. We obtained an expression for the probability of such interaction as a function of the surface-to-volume ratio (S/V). Comparing the obtained analytical expression with the results of computer simulation was performed. Shown the exponential dependence of the self-diffusion coefficient on the barrier pinning density.