In the last 30 days

• Open/close Graphene: fabrication methods and thermophysical properties

  Aleksandr V Eletskii et al 2011 Phys.-Usp. 54 227 Tag this article

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  Current research on graphene, a 2D hexagonal structure of carbon atoms, is presented. The structural features of and basic methods for obtaining graphene are discussed. The phononic properties of graphene and their dependent graphene characteristics are examined. In particular, how to measure the thermal conductivity of graphene is discussed and recent experimental and theoretical advances on this subject are described. The stability problems of 2D crystal structures are addressed and the dimensional effects in the dependence of graphene characteristics on the lateral size are discussed. Simulation methods for determining the phononic characteristics and thermal conductivity of graphene are reviewed.

• Open/close On surface electromagnetic waves

  V N Datsko and A A Kopylov 2008 Phys.-Usp. 51 101 Tag this article

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  The problem of surface electromagnetic waves is discussed. In spite of recent experimental evidence for the existence of Zenneck surface waves, theoretical consensus on this issue is lacking.

• Open/close Unpaired Majorana fermions in quantum wires

  A Yu Kitaev 2001 Phys.-Usp. 44 131 Tag this article

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  Certain one-dimensional Fermi systems have an energy gap in the bulk spectrum while boundary states are described by one Majorana operator per boundary point. A finite system of length L possesses two ground states with an energy difference proportional to exp(- L/ l ₀) and different fermionic parities. Such systems can be used as qubits since they are intrinsically immune to decoherence. The property of a system to have boundary Majorana fermions is expressed as a condition on the bulk electron spectrum. The condition is satisfied in the presence of an arbitrary small energy gap induced by proximity of a three-dimensional p-wave superconductor, provided that the normal spectrum has an odd number of Fermi points in each half of the Brillouin zone (each spin component counts separately).

• Open/close Horizons of petawatt laser technology

  Artem V Korzhimanov et al 2011 Phys.-Usp. 54 9 Tag this article

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  Recent advances in the development of superpower lasers are reviewed. A number of possibilities that the newly available petawatt-power level lasers open up in the physics of extreme light fields are discussed.

• Open/close Melting point of graphite and liquid carbon
  (Concerning the paper 'Experimental investigation of the thermal properties of carbon at high temperatures and moderate pressures' by EI Asinovskii, A V Kirillin, and A V Kostanovskii)

  Aleksandr I Savvatimskii 2003 Phys.-Usp. 46 1295 Tag this article

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  Experimental data from various authors on the graphite melting point are reviewed and compared with the results obtained by E I Asinovskii, A V Kirillin, and A V Kostanovskii as presented in their paper 'Experimental investigation of the thermal properties of carbon at high temperatures and moderate pressures' ( Usp. Fiz. Nauk. 172 931 (2002) [ Phys. Usp. 45 869 (2002)]). It is shown that a considerable amount of available information about the heating of graphite by an electrical current or a laser pulse remained unaccounted for in that paper. A comparative analysis of the data indicates the 4800 – 4900-K range as the most reliable melting point estimate for graphite under pressures ranging from 0.1 to 3.0 kbar.
• Open/close Transformation optics and metamaterials

  Alexander V Kildishev and Vladimir M Shalaev 2011 Phys.-Usp. 54 53 Tag this article

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  We review recent progress in developing a new class of specially designed optical metamaterial spaces with functionalities that cannot be obtained with conventional optics or natural materials. These optical metamaterial spaces could enable innovative paradigms of transformation optics pertinent to optical cloaking, sub-wavelength sensing, super-resolution imaging, magnifying hyperlenses, and light-concentrating devices. We also outline our recent development and deployment of an easy-to-use, multifaceted, on-line research environment for the nanophotonics research community. In particular, we show representative examples of two online software tools addressing a growing need for efficient numerical simulations in the area of transformation optics.

• Open/close Universal randomness

  Viktor S Dotsenko 2011 Phys.-Usp. 54 259 Tag this article

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  In the last two decades, it has been established that a single universal probability distribution function, known as the Tracy–Widom (TW) distribution, in many cases provides a macroscopic-level description of the statistical properties of microscopically different systems, including both purely mathematical ones, such as increasing subsequences in random permutations, and quite physical ones, such as directed polymers in random media or polynuclear crystal growth. In the first part of this review, we use a number of models to examine this phenomenon at a simple qualitative level and then consider the exact solution for one-dimensional directed polymers in a random environment, showing that free energy fluctuations in such a system are described by the universal TW distribution. The second part provides detailed appendix material containing the necessary mathematical background for the first part.

• Open/close Nonlinear aspects of quantum plasma physics

  Padma K Shukla and B Eliasson 2010 Phys.-Usp. 53 51 Tag this article

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  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 micromechanical 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, quantum plasmas have extremely high plasma number densities and low temperatures. Quantum plasmas 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, and holes) obey 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 allows the existence of very high-frequency dispersive electrostatic and electromagnetic waves (e.g., in the hard X-ray and gamma-ray regimes) with 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 focus on nonlinear electrostatic electron and ion plasma waves, novel aspects of three-dimensional 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 quasistationary 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.

• Open/close Circular photogalvanic effect in nanostructures

  Eugeniyus L Ivchenko 2002 Phys.-Usp. 45 1299 Tag this article

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• Open/close Electron transport in graphene

  S V Morozov et al 2008 Phys.-Usp. 51 744 Tag this article

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