223 research outputs found
Singularly perturbed spectral problems with Neumann boundary conditions
The paper deals with the Neumann spectral problem for a singularly perturbed
second order elliptic operator with bounded lower order terms. The main goal is
to provide a refined description of the limit behaviour of the principal
eigenvalue and eigenfunction. Using the logarithmic transformation we reduce
the studied problem to additive eigenvalue problem for a singularly perturbed
Hamilton-Jacobi equation. Then assuming that the Aubry set of the Hamiltonian
consists of a finite number of points or limit cycles situated in the domain or
on its boundary, we find the limit of the eigenvalue and formulate the
selection criterium that allows us to choose a solution of the limit
Hamilton-Jacobi equation which gives the logarithmic asymptotics of the
principal eigenfunction
Polarization Effects in Superfluid He
A theory of thermoelectric phenomena in superfluid is developed. It is
found an estimation of the dipole moment of helium atom arising due to electron
shell deformation caused by pushing forces from the side of its surrounding
atoms. The corresponding electric signal generated in a liquid consisting of
electrically neutral atoms by the ordinary sound waves is found extremely
small. The second sound waves in superfluid generate the polarization of
liquid induced by the relative accelerated motion of the superfluid and the
normal component. The derived ratio of the amplitudes of temperature and
electric polarization potential was proved to be practically temperature
independent. Its magnitude is in reasonable correspondence with the
experimental observations. The polarity of electric signal is determined by the
sign of temperature gradient in accordance with the measurements. The problem
of the roton excitations dipole moment is also discussed.Comment: 8 pages, no figure
Roton dipole moment
The roton excitation in the superfluid He-4 does not possess a stationary
dipole moment. However, a roton has an instantaneous dipole moment, such that
at any given moment one can find it in the state either with positive or with
negative dipole moment projection on its momentum direction. The instantaneous
value of electric dipole moment of roton excitation is evaluated. The result is
in reasonable agreement with recent experimental observation of the splitting
of microwave resonance absorption line at roton frequency under external
electric field.Comment: 5 page
Intermittency as a universal characteristic of the complete chromosome DNA sequences of eukaryotes: From protozoa to human genomes
Large-scale dynamical properties of complete chromosome DNA sequences of
eukaryotes are considered. By the proposed deterministic models with
intermittency and symbolic dynamics we describe a wide spectrum of large-scale
patterns inherent in these sequences, such as segmental duplications, tandem
repeats, and other complex sequence structures. It is shown that the recently
discovered gene number balance on the strands is not of random nature, and a
complete chromosome DNA sequence exhibits the properties of deterministic
chaos.Comment: 4 pages, 5 figure
On the electric activity of superfluid systems
The Keldysh's theory of superfluidity of rarefied electron-hole gas is
generalized to a case of possible pair polarizability. It was shown that
inhomogeneity of the system leads to dipole moment which is proportional to the
density gradient. The dipole moment appears also near boundaries of the system.
It was determined that quantized vortices in a magnetic field carry a real
electric charge. In He II at H=10 T and helium rotation velocity
s the charge density is about cm, where is the
electron charge.Comment: 5 pages V. 2: replaced incorrect g valu
On the mutual polarization of two He-4 atoms
We propose a simple method based on the standard quantum-mechanical
perturbation theory to calculate the mutual polarization of two atoms He^4.Comment: 9 pages, 1 table; the article is revised and the calculation is
essentially refined; v4: final version, the Introduction is delete
Some mechanisms of "spontaneous" polarization of superfluid He-4
Previously, a quantum "tidal" mechanism of polarization of the atoms of He-II
was proposed, according to which, as a result of interatomic interaction, each
atom of He-II acquires small fluctuating dipole and multipole moments, oriented
chaotically on the average. In this work, we show that, in the presence of a
temperature or density gradient in He-II, the originally chaotically oriented
tidal dipole moments of the atoms become partially ordered, which results in
volume polarization of He-II. It is found that the gravitational field of the
Earth induces electric induction U =10(-7)V in He-II (for vessel dimensions of
the order of 10 cm). We study also the connection of polarization and
acceleration, and discuss a possible nature of the electric signal dU = kdT/2e
observed by A.S. Rybalko in experiments with second sound.Comment: 13 pages; the calculation is extended and refined; v4: reconstructio
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