Exact solutions for equilibrium configurations of charged conducting liquid jets

A wide class of exact solutions is obtained for the problem of finding the equilibrium configurations of charged jets of a conducting liquid; these configurations correspond to the finite-amplitude azimuthal deformations of the surface of a round jet. A critical value of the linear electric charge density is determined, for which the jet surface becomes self-intersecting, and the jet splits into two. It exceeds the density value required for the excitation of the linear azimuthal instability of the round jet. Hence, there exists a range of linear charge density values, where our solutions may be stable with respect to small azimuthal perturbations.Comment: 7 pages, 5 figures, to appear in Physical Review

Dynamics of the Free Surface of a Conducting Liquid in a Near-Critical Electric Field

Near-critical behavior of the free surface of an ideally conducting liquid in an external electric field is considered. Based on an analysis of three-wave processes using the method of integral estimations, sufficient criteria for hard instability of a planar surface are formulated. It is shown that the higher-order nonlinearities do not saturate the instability, for which reason the growth of disturbances has an explosive character.Comment: 19 page

A Green's function decoupling scheme for the Edwards fermion-boson model

Holes in a Mott insulator are represented by spinless fermions in the fermion-boson model introduced by Edwards. Although the physically interesting regime is for low to moderate fermion density the model has interesting properties over the whole density range. It has previously been studied at half-filling in the one-dimensional (1D) case by numerical methods, in particular exact diagonalization and density matrix renormalization group (DMRG). In the present study the one-particle Green's function is calculated analytically by means of a decoupling scheme for the equations of motion, valid for arbitrary density in 1D, 2D and 3D with fairly large boson energy and zero boson relaxation parameter. The Green's function is used to compute some ground state properties, and the one-fermion spectral function, for fermion densities n=0.1, 0.5 and 0.9 in the 1D case. The results are generally in good agreement with numerical results obtained by DMRG and dynamical DMRG and new light is shed on the nature of the ground state at different fillings. The Green's function approximation is sufficiently successful in 1D to justify future application to the 2D and 3D cases.Comment: 19 pages, 7 figures, final version with updated reference

Statistical Description of Hydrodynamic Processes in Ionic Melts with taking into account Polarization Effects

Statistical description of hydrodynamic processes for ionic melts is proposed with taking into account polarization effects caused by the deformation of external ionic shells. This description is carried out by means of the Zubarev nonequilibrium statistical operator method, appropriate for investigations of both strong and weak nonequilibrium processes. The nonequilibrium statistical operator and the generalized hydrodynamic equations that take into account polarization processes are received for ionic-polarization model of ionic molten salts when the nonequilibrium averaged values of densities of ions number, their momentum, dipole momentum and total energy are chosen for the reduced description parameters. A spectrum of collective excitations is investigated within the viscoelastic approximation for ion-polarization model of ionic melts.Comment: 24 pages, RevTex4.1-format, no figure

Tuning the Non-local Spin-Spin Interaction between Quantum Dots with a Magnetic Field

We describe a device where the non-local spin-spin interaction between two quantum dots can be turned on and off and even changed sign with a very small magnetic field. The setup consists of two quantum dots at the edge of two two-dimensional electron gases (2DEGs). The quantum dots' spins are coupled through a RKKY-like interaction mediated by the electrons in the 2DEGs. A small magnetic field perpendicular to the plane of the 2DEG is used as a tuning parameter. When the cyclotron radius is commensurate with the interdot distance, the spin-spin interaction is amplified by a few orders of magnitude. The sign of the interaction is controlled by finely tuning the magnetic field. Our setup allows for several dots to be coupled in a linear arrangement and it is not restricted to nearest-neighbors interaction.Comment: 4 pages, 5 figures. Published versio

Entropy Production and Luminosity-Effective Temperature Relation for Main-Sequence Stars

Based on the maximum entropy production principle, a relation between luminosity and effective temperature for main-sequence stars is obtained. Simplicity of the derivation and absence of any empirical parameters in the result is a fundamental difference of the present method from the classic ones where equations of stellar structure are analyzed. Using available photometric data (Webda, GCG) for more than 7.5 thousand stars, it is shown that the obtained luminosity-temperature relation is better than previously used ones.Comment: 9 pages, 4 figure

The Steady State Distribution of the Master Equation

The steady states of the master equation are investigated. We give two expressions for the steady state distribution of the master equation a la the Zubarev-McLennan steady state distribution, i.e., the exact expression and an expression near equilibrium. The latter expression obtained is consistent with recent attempt of constructing steady state theormodynamics.Comment: 6 pages, No figures. A mistake was correcte

Research of the possibility of self-excited vibrations amplitude reducing when turning by the variation of the cutting speed

In this paper the results of research of the possibilities of self-excited vibrations suppression in turning by the cutting speed modulation are presented. The experimental approach to conduct the variative control of lathe main drive is described. The possibilities of main drive working in continuous rotation speed mode are researched.В статье приведены результаты исследования возможности подавления автоколебаний при точении модулированием скоростью резания. Описан экспериментальный подход осуществления вариативного управления приводом главного движения токарного станка. Исследованы возможности привода главного движения работы в режиме постоянного варьирования скоростью вращения