Showing papers by "Moscow Institute of Physics and Technology published in 2011"

On Combinatorial Expansion of the Conformal Blocks Arising from AGT Conjecture

Abstract: In their recent paper, Alday et al. (Lett Math Phys 91:167–197, 2010) proposed a relation between $${\mathcal{N}=2}$$ four-dimensional supersymmetric gauge theories and two-dimensional conformal field theories. As part of their conjecture they gave an explicit combinatorial formula for the expansion of the conformal blocks inspired by the exact form of the instanton part of the Nekrasov partition function. In this paper we study the origin of such an expansion from a CFT point of view. We consider the algebra $${\mathcal{A}={\sf Vir} \otimes\mathcal{H}}$$ which is the tensor product of mutually commuting Virasoro and Heisenberg algebras and discover the special orthogonal basis of states in the highest weight representations of $${\mathcal{A}}$$ . The matrix elements of primary fields in this basis have a very simple factorized form and coincide with the function called $${Z_{{\sf bif}}}$$ appearing in the instanton counting literature. Having such a simple basis, the problem of computation of the conformal blocks simplifies drastically and can be shown to lead to the expansion proposed in Alday et al. (2010). We found that this basis diagonalizes an infinite system of commuting Integrals of Motion related to Benjamin–Ono integrable hierarchy.

Interlayer interaction and relative vibrations of bilayer graphene.

Abstract: The van der Waals corrected first-principles approach (DFT-D) is for the first time applied for investigation of interlayer interaction and relative motion of graphene layers. A methodological study of the influence of parameters of calculations with the dispersion corrected and original PBE functionals on characteristics of the potential relief of the interlayer interaction energy is performed. Based on the DFT-D calculations, a new classical potential for interaction between graphene layers is developed. Molecular dynamics simulations of relative translational vibrations of graphene layers demonstrate that the choice of the classical potential considerably affects dynamic characteristics of graphene-based systems. The calculated low values of the Q-factor for these vibrations Q ≈ 10–100 show that graphene should be perfect for the use in fast-responding nanorelays and nanoelectromechanical memory cells.

High-Speed Boundary-Layer Instability: Old Terminology and a New Framework

Abstract: The discrete spectrum of disturbances in high-speed boundary layers is discussed with emphasis on singularities caused by synchronization of the normal modes. Numerical examples illustrate different spectral structures and jumps from one structure to another with small variations of basic flow parameters. It is shown that this singular behavior is due to branching of the dispersion curves in the synchronization region. Depending on the locations of the branch points, the spectrum contains an unstable mode or two. In connection with this, the terminology used for instability of high-speed boundary layers is clarified. It is emphasized that the spectrum branching may cause difficulties in stability analyses based on traditional linear stability theory and parabolized stability equations methods. Multiple-mode considerations and direct numerical simulations are needed to clarify this issue.

A direct proof of AGT conjecture at β = 1

Abstract: The AGT conjecture claims an equivalence of conformal blocks in 2d CFT and sums of Nekrasov functions (instantonic sums in 4d SUSY gauge theory). The conformal blocks can be presented as Dotsenko-Fateev β-ensembles, hence, the AGT conjecture implies the equality between Dotsenko-Fateev β-ensembles and the Nekrasov functions. In this paper, we prove it in a particular case of β = 1 (which corresponds to c = 1 at the conformal side and to ϵ1 + ϵ2 = 0 at the gauge theory side) in a very direct way. The central role is played by representation of the Nekrasov functions through correlators of characters (Schur polynomials) in the Selberg matrix models. We mostly concentrate on the case of SU(2) with 4 fundamentals, the extension to other cases being straightforward. The most obscure part is extending to an arbitrary β: for β ≠ 1, the Selberg integrals that we use do not reproduce single Nekrasov functions, but only sums of them.

Confirmation of the X(1835) and observation of the resonances X(2120) and X(2370) in J/ψ→γπ+π -η′

Abstract: With a sample of (225.2 +/- 2.8) x 10(6) J/psi events registered in the BESIII detector, J/psi -> gamma pi(+)pi(-)eta' is studied using two eta' decay modes: eta' -> pi(+)pi(-)eta and eta' -> gamma rho(0). The X(1835), which was previously observed by BESII, is confirmed with a statistical significance that is larger than 20 sigma. In addition, in the pi(+)pi(-)eta' invariant-mass spectrum, the X(2120) and the X(2370), are observed with statistical significances larger than 7.2 sigma and 6.4 sigma, respectively. For the X(1835), the angular distribution of the radiative photon is consistent with expectations for a pseudoscalar.

Production of J / ψ -meson pairs and 4 c tetraquark at the LHC

Abstract: Theoretical predictions for the $pp\ensuremath{\rightarrow}2J/\ensuremath{\psi}+X$ cross section at $\sqrt{s}=7\text{ }\text{ }\mathrm{TeV}$ with different kinematical restrictions are presented. Results are compared with the first LHCb data available. Special attention is paid to a possible signal from novel particles---tetraquarks build from two valence $c$-quarks and two valence $\overline{c}$-quarks. According to our estimates, it is quite possible to observe at least one of these states (tensor tetraquark) experimentally under LHCb conditions.

Commensurate-incommensurate phase transition in bilayer graphene

Abstract: A commensurate-incommensurate phase transition in bilayer graphene is investigated in the framework of the Frenkel-Kontorova model extended to the case of two interacting chains of particles. Analytic expressions are derived to estimate the critical unit elongation of one of the graphene layers at which the transition to the incommensurate phase takes place, the length and formation energy of incommensurability defects (IDs), and the threshold force required to start relative motion of the layers on the basis of dispersion-corrected density functional theory (DFT-D) calculations of the interlayer interaction energy as a function of the relative position of the layers. These estimates are confirmed by atomistic calculations using the DFT-D based classical potential. The possibility to measure the barrier for relative motion of graphene layers by the study of formation of IDs in bilayer graphene is discussed.

A Photochemical Model for the Venus Atmosphere at 47-112 km

Abstract: The model is intended to respond to the recent findings in the Venus atmosphere from the Venus Express and ground-based submillimeter and infrared observations. It extends down to 47 km for comparison with the kinetic model for the lower atmosphere (Krasnopolsky, V.A. [2007]. Icarus 191, 25–37) and to use its results as the boundary conditions. The model numerical accuracy is significantly improved by reduction of the altitude step from 2 km in the previous models to 0.5 km. Effects of the NUV absorber are approximated using the detailed photometric observations at 365 nm from Venera 14. The H2O profile is not fixed but calculated in the model. The model involves odd nitrogen and OCS chemistries based on the detected NO and OCS abundances. The number of the reactions is significantly reduced by removing of unimportant processes. Column rates for all reactions are given, and balances of production and loss may be analyzed in detail for each species. The calculated vertical profiles of CO, H2O, HCl, SO2, SO, OCS and of the O2 dayglow at 1.27 μm generally agree with the existing observational data; some differences are briefly discussed. The OH dayglow is ∼30 kR, brighter than the OH nightglow by a factor of 4. The H + O3 process dominates in the nightglow excitation and O + HO2 in the dayglow, because of the reduction of ozone by photolysis. A key feature of Venus’ photochemistry is the formation of sulfuric acid in a narrow layer near the cloud tops that greatly reduces abundances of SO2 and H2O above the clouds. Delivery of SO2 and H2O through this bottleneck determines the chemistry and its variations above the clouds. Small variations of eddy diffusion near 60 km result in variations of SO2, SO, and OCS at and above 70 km within a factor of ∼30. Variations of the SO2/H2O ratio at the lower boundary have similar but weaker effect: the variations within a factor of ∼4 are induced by changes of SO2/H2O by ±5%. Therefore the observed variations of the mesospheric composition originate from minor variations of the atmospheric dynamics near the cloud layer and do not require volcanism. NO cycles are responsible for production of a quarter of O2, SO2, and Cl2 in the atmosphere. A net effect of photochemistry in the middle atmosphere is the consumption of CO2, SO2, and HCl from and return of CO, H2SO4, and SO2Cl2 to the lower atmosphere. These processes may be balanced by thermochemistry in the lower atmosphere even without outgassing from the interior, though the latter is not ruled out by our models. Some differences between the model and observations and the previous models are briefly discussed.

Anomalous Josephson current via Majorana bound states in topological insulators.

Abstract: We propose a setup involving Majorana bound states (MBS) hosted by a vortex on a superconducting surface of a 3D topological insulator (TI). We consider a narrow channel drilled across a TI slab with both sides covered by $s$-wave superconductor. In the presence of a vortex pinned to such a channel, it acts as a ballistic nanowire connecting the superconducting surfaces, with a pair of MBS localized in it. The energies of the MBS possess a $4\ensuremath{\pi}$-periodic dependence on the superconductive phase difference $\ensuremath{\varphi}$ between the surfaces. It results in the appearance of an anomalous term in the current-phase relation ${I}_{a}(\ensuremath{\varphi})$ for the supercurrent flowing along the channel between the superconductive surfaces. We have calculated the shape of the $4\ensuremath{\pi}$-periodic function ${I}_{a}(\ensuremath{\varphi})$, as well as the dependence of its amplitude on temperature and system parameters.

Simple cellular automaton model for traffic breakdown, highway capacity, and synchronized flow

Abstract: We present a simple cellular automaton (CA) model for two-lane roads explaining the physics of traffic breakdown, highway capacity, and synchronized flow. The model consists of the rules ``acceleration,'' ``deceleration,'' ``randomization,'' and ``motion'' of the Nagel-Schreckenberg CA model as well as ``overacceleration through lane changing to the faster lane,'' ``comparison of vehicle gap with the synchronization gap,'' and ``speed adaptation within the synchronization gap'' of Kerner's three-phase traffic theory. We show that these few rules of the CA model can appropriately simulate fundamental empirical features of traffic breakdown and highway capacity found in traffic data measured over years in different countries, like characteristics of synchronized flow, the existence of the spontaneous and induced breakdowns at the same bottleneck, and associated probabilistic features of traffic breakdown and highway capacity. Single-vehicle data derived in model simulations show that synchronized flow first occurs and then self-maintains due to a spatiotemporal competition between speed adaptation to a slower speed of the preceding vehicle and passing of this slower vehicle. We find that the application of simple dependences of randomization probability and synchronization gap on driving situation allows us to explain the physics of moving synchronized flow patterns and the pinch effect in synchronized flow as observed in real traffic data.

Chiral magnetic effect in the soft-wall AdS/QCD model

Abstract: The essence of the chiral magnetic effect is generation of an electric current along an external magnetic field. Recently it has been studied by Rebhan, Schmitt, and Stricker within the Sakai-Sugimoto model, where it was shown to be zero. As an alternative, we calculate the chiral magnetic effect in soft-wall AdS/QCD and find a nonzero result with the natural boundary conditions. The mechanism of the dynamical neutralization of the chiral chemical potential via the string production is discussed in the dual two-form representation.

Brezin-Gross-Witten model as “pure gauge” limit of Selberg integrals

Abstract: The AGT relation identifies the Nekrasov functions for various \( \mathcal{N} = 2 \) SUSY gauge theories with the 2d conformal blocks, which possess explicit Dotsenko-Fateev matrix model (β-ensemble) representations the latter being polylinear combinations of Selberg integrals. The “pure gauge” limit of these matrix models is, however, a non-trivial multiscaling large-N limit, which requires a separate investigation. We show that in this pure gauge limit the Selberg integrals turn into averages in a Brezin-Gross-Witten (BGW) model. Thus, the Nekrasov function for pure SU(2) theory acquires a form very much reminiscent of the AMM decomposition formula for some model X into a pair of the BGW models. At the same time, X, which still has to be found, is the pure gauge limit of the elliptic Selberg integral. Presumably, it is again a BGW model, only in the Dijkgraaf-Vafa double cut phase.

Plasma filament investigation by transverse optical interferometry and terahertz scattering.

Abstract: Transverse plasma distribution with 10(17) cm(-3) maximum electron density and 150 μm transverse size in a plasma filament formed in air by an intense femtosecond laser pulse was measured by means of optical interferometry. Two orders of magnitude decay of the electron density within 2 ns was obtained by combined use of the interferometry and newly proposed terahertz scattering techniques. Excellent agreement was obtained between the measured plasma density evolution and theoretical calculation.

Study of chi(cJ) radiative decays into a vector meson

Abstract: The decays chi(cJ) -> gamma V ( V = phi, rho(0), omega) are studied with a sample of radiative psi' -> gamma chi(cJ) events in a sample of (1.06 +/- 0.04) X 10(8)psi' events collected with the BESIII detector. The branching fractions are determined to be: B(chi c1 -> gamma phi) = 25.8 +/- 5.2 +/- 2.3 X 10(-6), B(chi(c1) -> gamma rho(0)) = (228 +/- 13 +/- 22) X 10(-6), and B(chi(c1) -> gamma omega) = (69.7 +/- 7.2 +/- 6.6) X 10(-6). The decay chi(c1) -> gamma phi is observed for the first time. Upper limits at the 90% confidence level on the branching fractions for chi(c0) and chi(c2) decays into these final states are determined. In addition, the fractions of the transverse polarization component of the vector meson in chi(c1) -> gamma V decays are measured to be 0.29(-0.12-0.09)(+0.13+0.10) fo chi(c1) -> gamma phi, 0.158 +/- 0.037(-0.014)(+0.015) for chi(c1) -> gamma rho(o), and 0.247(-0.087-0.026)(+0.090+0.044) for chi(c1) -> gamma omega, respectively. The first errors are statistical and the second ones are systematic.

Effects of disorder and isotopic substitution in the specific heat and Raman scattering in LuB12

Abstract: Precision measurements of the specific heat and spectral intensity I(ω) of Raman scattering for Lu N B12 single crystal samples with various boron isotopes (N = 10, 11, nat) have been performed at low and intermediate temperatures. A boson peak in the low-frequency part of the I(ω) spectrum has been observed for the first time for lutetium dodecaboride at liquid nitrogen temperatures. It has been shown that low-temperature anomalies in the specific heat, along with the features of Raman spectra, can be interpreted in terms of the transition to a cageglass state at T* = 50−70 K, which appears when Lu3+ ions are displaced from the centrosymmetric position in cavities of a rigid covalent boron sublattice towards the randomly located boron vacancies. The concentrations of various two-level systems that correspond to two types of vibrational clusters with correlation lengths of 12–15 and 18–22 A, respectively, have been estimated. The vibrational density of states of LuB12 has been calculated from Raman spectra in the model of soft atomic potentials. An approach has been proposed to explain the dielectrization of the properties of the YbB12 compound at T < T*, as well as the features of the formation of magnetic structures in RB12 antiferromagnets (R = Tb, Dy, Ho, Er, Tm) and the suppression of superconductivity in LuB12.

Global Modeling of Radiatively Driven Accretion of Metals from Compact Debris Disks onto White Dwarfs

Abstract: Recent infrared observations have revealed the presence of compact (radii R ?) debris disks around more than a dozen metal-rich white dwarfs (WDs), likely produced by a tidal disruption of asteroids. Accretion of high-Z material from these disks may account for the metal contamination of these WDs. It was previously shown using local calculations that the Poynting-Robertson (PR) drag acting on the dense, optically thick disk naturally drives metal accretion onto the WD at the typical rate ?g?s?1. Here we extend this local analysis by exploring the global evolution of the debris disk under the action of the PR drag for a variety of assumptions about the disk properties. We find that massive disks (mass 1020 g), which are optically thick to incident stellar radiation, inevitably give rise to metal accretion at rates . The magnitude of and its time evolution are determined predominantly by the initial pattern of the radial distribution of the debris (i.e., ring-like versus disk-like) but not by the total mass of the disk. The latter determines only the disk lifetime, which can be several Myr or longer. The evolution of an optically thick disk generically results in the development of a sharp outer edge of the disk. We also find that the low-mass ( 1020 g), optically thin disks exhibit and evolve on a characteristic timescale ~105-106 yr, independent of their total mass.

Radiation-induced damage and evolution of defects in Mo

Abstract: The formation of defects in bcc Mo lattice as a result of 50-keV Xe bombardment is studied via atomistic simulation with an interatomic potential developed using the force-matching ab initio based approach. The defect evolution in the cascade is described. Diffusion and interaction of interstitials and vacancies are analyzed. Only small interstitial atom clusters form directly in the cascade. Larger clusters grow only via aggregation at temperatures up to 2000 K. Stable forms of clusters demonstrate one-dimensional diffusion with a very high diffusion coefficient and escape quickly to the open surface. Point vacancies have much lower diffusivity and do not aggregate. The possibility of a large prismatic vacancy loop formation near the impact surface as a result of fast recrystallization is revealed. The mobility of the vacancy dislocation loop segments is high, however, the motion of the entire loops is strongly hindered by neighbor point defects. This paper explains the existence of the large prismatic vacancy loops and the absence of the interstitial loops in the recent experiments with ion irradiation of Mo foils.

Modes of magnetic resonance in the spin-liquid phase of Cs2CuCl4.

Abstract: We report the observation of a frequency shift and splitting of the electron spin resonance (ESR) mode of the low-dimensional S=1/2 frustrated antiferromagnet Cs2CuCl4 in the spin-correlated state above the ordering temperature 0.62 K. The shift and splitting exhibit strong anisotropy with respect to the direction of the applied magnetic field and do not vanish in a zero field. The low-temperature evolution of the ESR is a result of the modification of the one-dimensional spinon continuum by the uniform Dzyaloshinskii-Moriya interaction within the spin chains.

Effects of density dependence of the effective pairing interaction on the first 2+ excitations and quadrupole moments of odd nuclei

Abstract: Excitation energies and transition probabilities of the first ${2}^{+}$ excitations in even tin and lead isotopes as well as the quadrupole moments of odd neighbors of these isotopes are calculated within the self-consistent theory of finite Fermi systems based on the energy density functional by Fayans et al. [Nucl. Phys. A 676, 49 (2000)]. The effect of the density dependence of the effective pairing interaction is analyzed in detail by comparing results obtained with volume and surface pairing. The effect is found to be noticeable. For example, the ${2}^{+}$ energies are systematically higher at 200--400 keV for the volume paring as compared with the surface-pairing case. However, on the average, both models reasonably agree with the data. Quadrupole moments of odd-neutron nuclei are very sensitive to the single-particle energy of the state $\ensuremath{\lambda}$ under consideration owing to the Bogolyubov factor (${u}_{\ensuremath{\lambda}}^{2}\ensuremath{-}{v}_{\ensuremath{\lambda}}^{2}$). A reasonable agreement with experiment for the quadrupole moments has been obtained for the most part of odd nuclei considered. The method used gives a reliable possibility to predict quadrupole moments of unstable odd nuclei, including very neutron rich ones.

On the 'Dotsenko–Fateev' representation of the toric conformal blocks

Abstract: We demonstrate that the recent ansatz of Maruyoshi and Yagi (2010 arXiv: 1009.5553), inspired by the original remark of R Dijkgraaf and C Vafa, reproduces the toric conformal blocks in the same sense as the spherical blocks given by the integral representation of Mironov et al (2010 J. High Energy Phys. JHEP02(2010)030 (arXiv: 0911.5721)) and Mironov et al (2010 arXiv: 1001.0563) with a peculiar choice of open integration contours for screening insertions. In other words, we provide some evidence that the toric conformal blocks are reproduced by appropriate β-ensembles not only in the large-N limit, but also at finite N. The check is explicitly performed at the first two levels for the 1-point toric functions. Generalizations to higher genera are briefly discussed.

An empirical study of common traffic congestion features based on traffic data measured in the USA, the UK, and Germany

Abstract: Based on real traffic data measured on American, UK and German freeways, we study common features of traffic congestion. We have found that traffic features [J] and [S] defining traffic phases “wide moving jam” (J) and “synchronized flow” (S) in Kerner’s three-phase theory are indeed common spatiotemporal traffic features observed in the UK, the USA and Germany. For the testing of Kerner’s “line J”, representing the propagation of the wide moving jam’s downstream front, four different methods for a study of moving jam propagation in empirical data are studied and compared for each congested traffic situation occurring in the three countries. A statistical study of velocities of wide moving jam fronts is presented, which has been performed through the analysis of database containing more than 280.000 min of observed wide moving jams measured on about 1200 km long freeway network in Hessen (Germany) during more than two years.

New opportunities provided by modernized small-angle neutron scattering two-detector system instrument (YuMO)

Abstract: Main features of the modernized small-angle neutron scattering spectrometer (YuMO) at IBR-2M pulsed reactor are described. New installations for sample environment of the spectrometer are highlighted. The modernized SANS instrument (YuMO) is equipped with a new type of position sensitive detector as well as two detector system which provide a unique dynamic range (Qmax/Qmin ratio is about 90). Sample environment is extended with a magnetic system (magnetic field about 2.5 Tesla), automated high pressure setup which allows simultaneous SANS and volumetric high pressure studies and light illumination system. In particular, these developments led to considerable improvements of resolution of the instrument (about 1%) and opened the possibility to study anisotropic materials and perform efficient high pressure studies.

Optical rogue waves in telecommunication data streams

Abstract: Large broadening of short optical pulses due to fiber dispersion leads to a strong overlap in information data streams resulting in statistical deviations of the local power from its average. We present a theoretical analysis of rare events of high-intensity fluctuations---optical freak waves---that occur in fiber communication links using bit-overlapping transmission. Although the nature of the large fluctuations examined here is completely linear, as compared to commonly studied freak waves generated by nonlinear effects, the considered deviations inherit from rogue waves the key features of practical interest---random appearance of localized high-intensity pulses. We use the term ``rogue wave'' in an unusual context mostly to attract attention to both the possibility of purely linear statistical generation of huge amplitude waves and to the fact that in optics the occurrence of such pulses might be observable even with the standard Gaussian or even rarer-than-Gaussian statistics, without imposing the condition of an increased probability of extreme value events.

Dynamics of dust structures in a dc discharge under action of axial magnetic field

Abstract: Results of experiments on the formation of dusty plasma structures in a stratified dc discharge in axial magnetic fields up to 2500 G are presented. The rotation of the rather small and planar dusty plasma structures has been observed. As the field increases, the inversion of the structure rotation occurs, and when it reaches 700 G, the displacement of dust particles from the axial region of the discharge to the periphery, along with the rotation continuation, is observed. The explanation of the features in the dynamical behavior of the dust particles in the discharge, in particular the rotation inversion, is proposed.

Evidence for the suppressed decay B-→DK-, D→K+π-

Abstract: The suppressed decay chain B- -> DK-, D -> K+pi(-), where D indicates a (D) over bar (0) or D-0 state, provides important information on the CP-violating angle phi(3). We measure the ratio R-DK of the decay rates to the favored mode B- -> DK-, D -> K+pi(-) to be R-DK = [1.63(-0.41)(+0.44)(stat)(-0.13)(+0.07)(syst)] x 10(-2), which indicates the first evidence of the signal with a significance of 4.1 sigma. We also measure the asymmetry A(DK) between the charge-conjugate decays to be A(DK) = -0.39(-0.28)(+0.26)(stat)(-0.03)(+0.04)(syst). The results are based on the full 772 x 10(6) B (B) over bar pair data sample collected at the Gamma(4S) resonance with the Belle detector.

Near-threshold femtosecond laser fabrication of one-dimensional subwavelength nanogratings on a graphite surface

Abstract: Superimposed one-dimensional quasiperiodic gratings with multiple periods \ensuremath{\Lambda} \ensuremath{\approx} 110--800 nm well below or comparable to the pump laser wavelength of 744 nm, and ridge orientations perpendicular to the linear polarization of infrared femtosecond laser pulses, were fabricated after multiple near-threshold laser shots on a planar surface of quasimonocrystalline graphite in ambient air. The broad range of the grating periods corresponds to the large number of spatial Fourier harmonics of the final nanorelief (up to $m=7$th order, ${\ensuremath{\Lambda}}_{m}\ensuremath{\approx}800$ nm/$m=110--800$ nm), qualitatively representing the nonsinusoidal profile of the laser-induced intermediate surface relief (the set of periodic, broadly spaced narrow nanotrenches), which provides the corresponding multiangle diffraction of the incident femtosecond laser pulses. Experimental measurements and modeling of the transient optical constants of the photoexcited graphite justify the excitation, at the first stage, of the first-order (${\ensuremath{\Lambda}}_{1}\ensuremath{\approx}800$ nm) surface plasmon-polaritonic (SPP) wave on the photo-excited initial planar graphite surface becoming metallic via photo-generation of dense electron hole plasma ($\ensuremath{\sim}{10}^{21}$ cm${}^{\ensuremath{-}3}$). Such an SPP wave provides intermediate nanorelief in the form of the nonsinusoidal surface grating via its interference with the incident laser wave, resulting under near-threshold laser irradiation conditions in the highly localized surface ablation of the material in the interference maxima. During the next stage, the multiperiod subwavelength nanogratings develop through the multiangle diffraction of the multiple incident laser pulses on the intermediate nonsinusoidal surface grating.

Surface plasmon polariton amplification in metal-semiconductor structures

Abstract: We propose a novel scheme of surface plasmon polariton (SPP) amplification that is based on a minority carrier injection in a Schottky diode. This scheme uses compact electrical pumping instead of bulky optical pumping. Compact size and a planar structure of the proposed amplifier allow one to utilize it in integrated plasmonic circuits and couple it easily to passive plasmonic devices. Moreover, this technique can be used to obtain surface plasmon lasing.