Physics-Uspekhi

Exotic charmonium

Tue, 09 Mar 2010 21:00:01 GMT

G.V. Pakhlova, P.N. Pakhlov, S.I. Eidel’man

The most significant results on the spectroscopy, production and decay of charmonium and charmonium-like states are reviewed. The surprise-filled physics of charmonium is currently attracting a lot of experimental and theoretical attention. Unexpected properties exhibited by numerous discovered states fail to be explained by current theory which claims instead the existence in the spectra of charmonium-like particles of exotic systems different from usual bound states.

Surface states in photonic crystals

Tue, 09 Mar 2010 21:00:02 GMT

A.P. Vinogradov, A.V. Dorofeenko, A.M. Merzlikin, A.A. Lisyansky

Propagation of surface electromagnetic waves along photonic crystal (PC) boundaries is examined. It is shown that in a number of cases these waves are backward. The nature of the surface electromagnetic states, localized at the PC boundary, is discussed; these states transfer no energy along the boundary (their tangential wave number is zero). An analogy with the well-known Tamm and Shockley surface states in solid state physics is drawn. It is shown that in the case of PC both types of states can be considered as the Tamm ones. Experimental results on the observation of the surface states are presented. A system using an external magnetic field to control a surface state is considered.

Equipment and techniques for carbon nanotube research

Tue, 09 Mar 2010 21:00:03 GMT

A.I. Vorob’eva

Many nanotube applications, in particular those in nanoelectronic systems, require nanotubes with strictly defined electrophysical parameters. This paper reviews equipment and techniques for studying and measuring the most important of these parameters. Theoretical and experimental parameter values obtained from different techniques are compared. Ways of preparing nanotube-containing samples for investigation and measurement purposes are examined.

Classification of Ge hut clusters in arrays formed by molecular beam epitaxy at low temperatures on the Si(001) surface

Tue, 09 Mar 2010 21:00:04 GMT

L.V. Arapkina, V.A. Yuryev

Ge hut clusters forming quantum dot arrays on the Si(001) surface in the process of low-temperature ultrahigh-vacuum molecular beam epitaxy are morphologicaly investigated and classified using in situ scanning tunnelling microscopy. It is found that two main Ge hut cluster types — pyramidal and wedge-shaped — have different atomic structures, and it is concluded that shape transitions between the two are impossible. Derivative cluster species — obelisks (or truncated wedges) and accreted wedges — are revealed and investigated for the first time and shown to start dominating at high Ge coverages. The uniformity of cluster arrays is shown to be controlled by the scatter in the length of wedge-like clusters. At low growth temperatures (360 °C), cluster nucleation during the growth of the array is observed for all values of Ge coverage except for a particular point at which the arrays are more uniform than at higher or lower coverages. At higher temperatures (530 °C), no cluster nucleation is observed after the initial formation of the array.

On some correlations in seismodynamics and on two components of Earth's seismic activity

Tue, 09 Mar 2010 21:00:05 GMT

A.M. Fridman, E.V. Polyachenko, N.R. Nasyrkanov

A brief critical review of papers published in Fizika Zemli is presented.

Honoring the 90th birthday of Academician I M Khalatnikov (Scientific session of the Physical Sciences Division of the Russian Academy of Sciences, 21 October 2009)

Tue, 09 Mar 2010 21:00:06 GMT

A.Yu. Kamenshchik, V.L. Pokrovsky, I.B. Khriplovich

QCD and the physics of hadronic collisions

Thu, 11 Feb 2010 21:00:01 GMT

M.L. Mangano

We review the basic principles underlying the use of quantum chromodynamics in understanding the structure of high-Q² processes in high-energy hadronic collisions. Several applications of relevance to the Tevatron and the LHC are illustrated.

Nonlocal electron kinetics in gas discharge plasma

Thu, 11 Feb 2010 21:00:02 GMT

L.D. Tsendin

The field of electron kinetics in extremely nonequilibrium glow discharge plasma is reviewed starting from the classical works of Langmuir. It is shown that it is only in terms of kinetics that many aspects of nonequilibrium plasma — such as the structure of near-electrode regions; spatial profiles of ionization and luminosity; strata and particle and energy flows — can be adequately understood.

Optical discharge in the field of a Bessel laser beam

Thu, 11 Feb 2010 21:00:03 GMT

L.N. Pyatnitskii

The propagation features of laser radiation are discussed for the case of axiconic focusing. Issues explored include the nature of gas breakdown in the field of a Bessel laser beam, the gas-dynamic expansion of the breakdown plasma, and how optical discharges and plasma channels are structured.

Experimental methods for determining the melting temperature and the heat of melting of clusters and nanoparticles

Thu, 11 Feb 2010 21:00:04 GMT

G.N. Makarov

Unlike macroscopic objects, clusters and nanoparticles lack a definite melting temperature at a given pressure but rather have their solid and liquid phases coexistent in a certain temperature range and their melting temperature dependent on the particle size. As the particle size decreases, the melting temperature becomes fundamentally difficult to define. This review examines methods for measuring the melting temperature and the heat of melting of clusters and nanoparticles. The temperature (internal energy) of the particles is defined and how it affects the properties of and processes involving the particles is discussed. The melting features of clusters and nanoparticles versus bulk materials are examined. Early methods of determining the melting temperature of large clusters are described. New precision methods of measuring the melting temperature and the heat of melting of clusters are discussed, which use clusters themselves as "high-sensitivity calorimeters" to measure energy. Laser-based nanoparticle melting techniques are outlined.

Ferroelectric nanocrystals and their switching

Thu, 11 Feb 2010 21:00:05 GMT

V.M. Fridkin, R.V. Gaynutdinov, S. Ducharme

The behavior of ferroelectricity at the nanoscale is the focus of increasing research activity because of intense interest in the fundamental nature of spontaneous order in condensed-matter systems and because of the many practical applications of ferroelectric thin films and nanocrystals to, for example electromechanical transducers, infrared imaging sensors and nonvolatile memories. In recent years there has been increasing interest in the growth and characterization of ferroelectric nanocrystals. In spite of the limited number of reported results, we hope that this will be a useful review of important recent developments.

Energy density calculations for ball-lightning-like luminous silicon balls

Thu, 11 Feb 2010 21:00:06 GMT

G.S. Paiva, J.V. Ferreira, C.C. Bastos, M.V.P. dos Santos, A.C. Pavão

The energy density of a luminous silicon ball [Phys. Rev. Lett. 98 048501 (2007)] is calculated for a model with a metal core surrounded by an atmosphere of silicon oxides. Experimental data combined with the molecular orbital calculations of the oxidation enthalpy lead to a mean energy density of 3.9 MJ m^-3, which is within the range of estimates from other ball lightning models. This result provides a good evidence to support the silicon-based model.

The superconductor-insulator quantum phase transition

Tue, 05 Jan 2010 21:00:01 GMT

V.F. Gantmakher, V.T. Dolgopolov

The current understanding of the superconductor – insulator transition is discussed level by level in a cyclic spiral-like manner. At the first level, physical phenomena and processes are discussed which, while of no formal relevance to the topic of transitions, are important for their implementation and observation; these include superconductivity in low electron density materials, transport and magnetoresistance in superconducting island films and in highly resistive granular materials with superconducting grains, and the Berezinsky – Kosterlitz – Thouless transition. The second level discusses and summarizes results from various macroscopic approaches to the problem, whether based on the Bardeen – Cooper – Schrieffer theory (the disorder-induced reduction in the superconducting transition temperature; the key role of Coulomb blockade in high-resistance grained superconductors; superconducting fluctuations in a strong magnetic field) or on the theory of the Bose – Einstein condensation. A special discussion is given to phenomenological scaling theories. Experimental investigations, primarily transport measurements, make the contents of the third level and are for convenience classified by the type of material used (ultrathin films, variable composition materials, high-temperature superconductors, superconductor – poor metal transitions). As a separate topic, data on nonlinear phenomena near the superconductor – insulator transition are presented. At the final, summarizing, level the basic aspects of the problem are enumerated again to identify where further research is needed and how this research can be carried out. Some relatively new results, potentially of key importance in resolving the remaining problems, are also discussed.

Nonlinear aspects of quantum plasma physics

Tue, 05 Jan 2010 21:00:02 GMT

P.K. Shukla, B. Eliasson

Dense quantum plasmas are ubiquitous in planetary interiors and in compact astrophysical objects (e.g. the interior of white dwarf stars, in magnetars etc.), in semiconductors and micro-mechanical systems, as well as in the next generation intense laser-solid density plasma interaction experiments and in quantum X-ray free-electron lasers. In contrast to classical plasmas, one encounters extremely high plasma number density and low temperature in quantum plasmas. The latter are composed of electrons, positrons and holes, which are degenerate. Positrons (holes) have the same (slightly different) mass as electrons, but opposite charge. The degenerate charged particles (electrons, positrons, holes) follow the Fermi – Dirac statistics. In quantum plasmas, there are new forces associated with (i) quantum statistical electron and positron pressures, (ii) electron and positron tunneling through the Bohm potential, and (iii) electron and positron angular momentum spin. Inclusion of these quantum forces provides possibility of very high-frequency dispersive electrostatic and electromagnetic waves (e.g. in the hard X-ray and gamma rays regimes) having extremely short wavelengths. In this review paper, we present theoretical backgrounds for some important nonlinear aspects of wave-wave and wave-electron interactions in dense quantum plasmas. Specifically, we shall focus on nonlinear electrostatic electron and ion plasma waves, novel aspects of 3D quantum electron fluid turbulence, as well as nonlinearly coupled intense electromagnetic waves and localized plasma wave structures. Also discussed are the phase space kinetic structures and mechanisms that can generate quasi-stationary magnetic fields in dense quantum plasmas. The influence of the external magnetic field and the electron angular momentum spin on the electromagnetic wave dynamics is discussed. Finally, future perspectives of the nonlinear quantum plasma physics are highlighted.

The near-field microscope as a tool for studying nanoparticles

Tue, 05 Jan 2010 21:00:03 GMT

I.S. Osad’ko

The oscillating electric dipole field induced by laser light at the probe tip of the near field microscope is shown to allow a higher resolution compared to the conventional optical microscope.

On the Bose – Einstein condensate partition function for an ideal gas

Tue, 05 Jan 2010 21:00:04 GMT

E.D. Trifonov, S.N. Zagoulaev

Recursive approaches determining the canonical ideal Bose gas partition function are reviewed that enable the Bose – Einstein condensate occupation probability to be calculated for a finite number of particles ensemble where, the thermodynamic limit approximation fails. In addition to the earlier known method recursive in the number of particles, an iteration procedure on the number of quantum states is proposed. The efficiency of both methods is demonstrated for an ideal Bose gas in a three-dimensional isotropic harmonic trap.

Submerged Landau jet: exact solutions, their meaning and application

Tue, 05 Jan 2010 21:00:05 GMT

G.I. Broman, O.V. Rudenko

Exact hydrodynamic solutions generalizing the Landau submerged jet solution are reviewed. It is shown how exact inviscid solutions can be obtained and how boundary layer viscosity can be included by introducing parabolic coordinates. The use of exact solutions in applied hydrodynamics and acoustics is discussed. A historical perspective on the discovery of the class of exact solutions and on the analysis of their physical meaning is presented.

On the 70th anniversary of the Leontovich boundary condition (comments on "The generalization of the Leontovich approximation to electromagnetic fields at the insulator-metal interface" by V I Alshits and V N Lyubimov)

Tue, 05 Jan 2010 21:00:06 GMT

A.V. Guglielmi

The question of Leontovich's 70-year old boundary condition for the surface of a well conducting body is discussed. Doubt is cast on the assertion by Alshits and Lyubimov (Usp. Fiz. Nauk 179 865 (2009) [Phys. Usp. 52 815 (2009)]) that this boundary condition is more accurate that Leontovich himself believed. The 1940 paper by Rytov written on the suggestion of Leontovich is indicated as evidence for the latter's full awareness of exactly how accurate his proposed boundary condition was.

In memory of Vitaly Lazarevich Ginzburg

Mon, 07 Dec 2009 21:00:01 GMT

M.S. Aksenteva, V.A. Rubakov, O.V. Rudenko

Electron - phonon interaction in high-temperature superconductors

Mon, 07 Dec 2009 21:00:02 GMT

A.S. Mishchenko

Results indicating an important role of the electron - phonon interaction in high-temperature superconductivity compounds are presented with emphasis on its implications for angle resolved photoemission and optical conductivity. The dimensionless phonon coupling constant λ is determined by comparing the experimental and theoretical results. While undoped materials are in the strong coupling (λ-near-unity) regime, hole doping decreases λ, bringing compounds to the intermediate coupling regime at the optimum hole concentrations.

On the use of chaotic synchronization for secure communication

Mon, 07 Dec 2009 21:00:03 GMT

A.A. Koronovskii, O.I. Moskalenko, A.E. Hramov

Research on the secure communication applications of chaotic synchronization is reviewed. A number of secure communication methods and devices using different types of synchronous behavior are examined. For the purpose of comparison of existing methods, quantitative efficiency characteristics are introduced and estimated. An extremely noise-stable, generalized synchronization-based, secure information transmission method is proposed. All of the methods considered are systematically checked for efficiency for the first time by numerically simulating unidirectionally coupled chaotic Rössler systems for use as transmitting and receiving generators. Key advantages and disadvantages of secure information transmission schemes using synchronized chaotic oscillations are discussed.

Passion for symmetry

Mon, 07 Dec 2009 21:00:04 GMT

M. Kobayashi, T. Maskawa, Y. Nambu

NOBEL LECTURES IN PHYSICS — 2008 (in Russian)

CP violation and flavour mixing

Mon, 07 Dec 2009 21:00:05 GMT

M. Kobayashi

NOBEL LECTURES IN PHYSICS — 2008 (in Russian)

What does CP violation tell us?

Mon, 07 Dec 2009 21:00:06 GMT

T. Maskawa

NOBEL LECTURES IN PHYSICS — 2008 (in Russian)

P N Lebedev Physical Institute RAS — 75 years (Joint session of the P N Lebedev Physical Institute Research Council and the scientific session of the Physical Sciences Division of the Russian Academy of Sciences and the United Physical Society of the Russian Federation, 6 April 2009)

Sun, 29 Nov 2009 21:00:01 GMT

G.A. Mesyats, B.M. Bolotovsky, Yu.V. Kopaev, N.S. Kardashev, G.T. Zatsepin, T.M. Roganova, A.V. Masalov, V.L. Velichansky, M.A. Gubin, R.D. Dagkesamanskii

P N Lebedev Physical Institute RAS: past, present and future

Sun, 29 Nov 2009 21:00:02 GMT

G.A. Mesyats

This paper reviews the history of the P N Lebedev Physical Institute of the Russian Academy of Sciences. Its major achievements are discussed, current activities are described, and future prospects are outlined.

Vavilov-Cherenkov radiation: discovery and applications

Sun, 29 Nov 2009 21:00:03 GMT

B.M. Bolotovsky

An account is given of how the Vavilov-Cherenkov effect was discovered. Some important applications of the effect are described.

Toroidal ordering in crystals

Sun, 29 Nov 2009 21:00:04 GMT

Yu.V. Kopaev

Phase transitions are discussed occurring to ordered states that correspond to the toroidal family of multipoles known in electrodynamics. The ordering of toroidal moments may either occur simultaneously with their formation (as in superconductivity) or may follow it (at lower temperature). In addition to electrodynamic toroidal moments corresponding to poloidal charge currents or a spin configuration, a toroidal state corresponding to poloidal spin currents is possible.

RadioAstron: a radio telescope many times the size of the Earth. Research program

Sun, 29 Nov 2009 21:00:05 GMT

N.S. Kardashev

A number of earthbound radio telescopes and one in a terrestrial orbit with the apogee at about the Earth - Moon distance have been combined to make an interferometer that provides an angular resolution of up to a few microarcseconds for exploring astronomical objects such as pulsars, star formation regions and black holes. Black hole horizon physics, cosmic ray acceleration regions and assumed wormhole entrances are becoming accessible to study for the first time.

Cosmic ray investigations

Sun, 29 Nov 2009 21:00:06 GMT

G.T. Zatsepin, T.M. Roganova

An historical review is given of cosmic ray research carried out at the P N Lebedev Institute from the time the Institute entered the field to the present. The key stages and directions of the research are outlined. The pioneering studies on the nuclear cascade process in extensive air showers and on the Vavilov - Cherenkov radiation are discussed. Some work on the origin of the cosmic rays is reviewed. The latest data on superhigh energy particle detection at the Pierre Auger Observatory and HiRes installation are presented.

Study of layered superconductors in the framework of electron—phonon coupling theory

Fri, 09 Oct 2009 20:00:01 GMT

I.N. Askerzade

In this review we summarize a number of recent developments in the study of layered superconductors using e-phonon Eliashberg theory. Critical temperature of layered superconductors is calculated using Eliashberg theory. Influence of nonadiabacity effects on the critical temperature in layered superconductors is considered. Influence of Coulomb repulsion on the critical temperature is investigated taking into account the arbitrary thicknesses of conducting layers. Bardeen—Cooper—Schrieffer (BCS) equations for layered superconductors are applied for the calculation of a specific heat jump, which is smaller than in the case of isotropic BCS theory. The plasmon spectrum of layered superconductors with arbitrary thicknesses of conducting layers is calculated. Influence of fluctuations in the phase of the order parameter on the critical temperature of layered superconductors is studied using Ginzburg—Landau functional for free energy. The results are shown to be in qualitative agreement with some experimental data for cuprate superconductors and recently discovered MgB₂.

High and ultra-high pressure research on phase transformations in 3d-metal oxides: current progress

Fri, 09 Oct 2009 20:00:02 GMT

I.S. Lyubutin, A.G. Gavriliuk

Theory predicts that under a sufficient pressure magnetic systems with strong electron correlations undergo an insulator-metal phase transition which is accompanied by the collapse of the localized magnetic moment and also involves a structural phase transition. The pressures in question are, however, very high and hard to achieve, therefore until recently such scenario has not been observed experimentally. This paper reviews recent experimental studies of the influence of high and ultra-high pressures on the magnetic and crystal structure, the electronic and spin states, and the transport properties of 3d-metal oxides of different crystal structure.

Fractional differential approach to dispersive transport in semiconductors

Fri, 09 Oct 2009 20:00:03 GMT

R.T. Sibatov, V.V. Uchaikin

A novel approach using equations with fractional order derivatives to describe dispersive transport in disordered semiconductors is described. A relationship between the self-similarity of dispersive transport, stable limiting distributions and kinetic equations with fractional derivatives is established. It is shown that unlike the well-known Scher—Montroll and Arkhipov—Rudenko models, which are in a sense alternative to the normal transport model, fractional differential equations provide a unified mathematical framework for describing normal and dispersive transport. The fractional differential formalism allows the equations of bipolar transport to be written down and transport in distributed dispersion systems to be described. The relationship between fractional transport equations and the generalized limit theorem reveals the probabilistic aspects of the phenomenon in which a dispersive to Gaussian transport transition occurs in a time-of-flight experiment as the applied voltage is decreased and/or the sample thickness increased.

On mass transfer thermodynamics in nonisothermal molecular liquid mixtures

Fri, 09 Oct 2009 20:00:04 GMT

S.N. Semenov, M.E. Schimpf

Mass transfer in a nonisothermal binary molecular mixture is systematically discussed in terms of nonequilibrium thermodynamics, allowing, for the first time, a noncontradictory and unambiguous description of the process. The thermodynamic approach and hydrodynamic approach are compared, revealing that nonequilibrium thermodynamics and physicochemical hydrodynamics yield essentially the same results for molecular systems. The limits of applicability for the suggested version of the thermodynamic approach are determined for large particles.

Prospects for the development of fundamental physics and astronomy (Scientific session of the General Meeting of the Physical Sciences Division of the Russian Academy of Sciences, 12 December 2008)

Fri, 09 Oct 2009 20:00:05 GMT

L.M. Zelenyi

The Solar system, current understanding and future prospects

Fri, 09 Oct 2009 20:00:06 GMT

L.M. Zelenyi, A.V. Zakharov, L.V. Ksanfomality

The present understanding of the origin and properties of the Solar system is discussed and what is known about extrasolar planets is reviewed. The current status of and future prospects for space exploration in Russia and elsewhere are examined. (This paper is an extended version of "Prospects for the Russian research program on Solar system physical processes" by L.M. Zelenyi, presented at the scientific session "Prospects for the development of fundamental physics and astronomy" at the RAS Physical Sciences Division general meeting held 15 December 2008.)