Griffiths phases in the strongly disordered Kondo necklace model

The effect of strong disorder on the one-dimensional Kondo necklace model is studied using a perturbative real-space renormalization group approach which becomes asymptotically exact in the low energy limit. The phase diagram of the model presents a random quantum critical point separating two phases; the {\em random singlet phase} of a quantum disordered XY chain and the random Kondo phase. We also consider an anisotropic version of the model and show that it maps on the strongly disordered transverse Ising model. The present results provide a rigorous microscopic basis for non-Fermi liquid behavior in disordered heavy fermions due to Griffiths phases.Comment: 4 pages, 4 figure

The effect of the Abrikosov vortex phase on spin and charge states in magnetic semiconductor-superconductor hybrids

We explore the possibility of using the inhomogeneous magnetic field carried by an Abrikosov vortex in a type-II superconductor to localize spin-polarized textures in a nearby magnetic semiconductor quantum well. We show how Zeeman-induced localization induced by a single vortex is indeed possible, and use these results to investigate the effect of a periodic vortex array on the transport properties of the magnetic semiconductor. In particular, we find an unconventional Integer Quantum Hall regime, and predict directly testable experimental consequences due to the presence of the periodic spin polarized structure induced by the superconducting vortex lattice in the magnetic semiconductor.Comment: 12 pages, 15 figure

Phase diagram of the Kondo necklace: a mean-field renormalization group approach

In this paper we investigate the magnetic properties of heavy fermions in the antiferromagnetic and dense Kondo phases in the framework of the Kondo necklace model. We use a mean field renormalization group approach to obtain a temperature versus Kondo coupling $(T-J)$ phase diagram for this model in qualitative agreement with Doniach's diagram, proposed on physical grounds. We further analyze the magnetically disordered phase using a two-sites approach. We calculate the correlation functions and the magnetic susceptibility that allow to identify the crossover between the spin-liquid and the local moment regimes, which occurs at a {\em coherence} temperature.Comment: 5 figure

Chaotic Motion of Relativistic Electrons Driven by Whistler Waves

Canonical equations governing an electron motion in electromagnetic field of the whistler mode waves propagating along the direction of an ambient magnetic field are derived. The physical processes on which the equations of motion are based .are identified. It is shown that relativistic electrons interacting with these fields demonstrate chaotic motion, which is accompanied by the particle stochastic heating and significant pitch angle diffusion. Evolution of distribution functions is described by the Fokker-Planck-Kolmogorov equations. It is shown that the whistler mode waves could provide a viable mechanism for stochastic energization of electrons with energies up to 50 MeV in the Jovian magnetosphere

Extremely broadband ultralight thermally emissive metasurfaces

We report the design, fabrication and characterization of ultralight highly emissive metaphotonic structures with record-low mass/area that emit thermal radiation efficiently over a broad spectral (2 to 35 microns) and angular (0-60 degrees) range. The structures comprise one to three pairs of alternating nanometer-scale metallic and dielectric layers, and have measured effective 300 K hemispherical emissivities of 0.7 to 0.9. To our knowledge, these structures, which are all subwavelength in thickness are the lightest reported metasurfaces with comparable infrared emissivity. The superior optical properties, together with their mechanical flexibility, low outgassing, and low areal mass, suggest that these metasurfaces are candidates for thermal management in applications demanding of ultralight flexible structures, including aerospace applications, ultralight photovoltaics, lightweight flexible electronics, and textiles for thermal insulation

Effects of memristor-based coupling in the ensemble of FitzHugh-Nagumo elements

In this paper, we study the impact of electrical and memristor-based couplings on some neuron-like spiking regimes, previously observed in the ensemble of two identical FitzHugh-Nagumo elements with chemical excitatory coupling. We demonstrate how increasing strength of these couplings affects on such stable periodic regimes as spiking in-phase, anti-phase and sequential activity. We show that the presence of electrical and memristor-based coupling does not essentially affect regimes of in-phase activity. Such regimes do not changes remaining stable ones. However, it is not the case for regimes of anti-phase and sequential activity. All such regimes can transform into periodic or chaotic ones which are very similar to the regimes of in-phase activity. Concerning the regimes of sequential activity, this transformation depends continuously on the coupling parameters, whereas some anti-phase regimes can disappear via a saddle-node bifurcation and nearby orbits tend to regimes of in-phase activity. Also, we show that new interesting neuron-like phenomena can appear from the regimes of sequential activity when increasing the strength of electrical and/or memristor-based coupling. The corresponding regimes can be associated with the appearance of spiral attractors containing a saddle-focus equilibrium with homoclinic orbit and, thus, they correspond to chaotic motions near the invariant manifold of synchronization, which contains all in-phase limit cycles. Such new regimes can lead to the emergence of extreme events in the system of coupled neurons. In particular, the interspike intervals can become arbitrarily large when orbit pass very close to the saddle-focus. Finally, we show that the further increase in the strength of electrical coupling and/or memristor-based coupling leads to decreasing interspike intervals and, thus, it helps to avoid such extreme behavior

The optimization of the system of taxpayers’ state registration using road mapping method

In the state registration of taxpayers is the basis for creation of Unified State Register of Taxpayers (as to legal entities and individual entrepreneurs), which allows controlling completeness and timeliness of taxes’ payment and, consequently, providing formation of budget. The paper analyses legal framework for regulation of taxpayers’ registration, distinguishes the particularities of registration of organizations and private persons (individual entrepreneurs). There is also an analysis of applicable practice of taxpayers’ registration in Russia and the Republic of Mordovia. The positive trends (formation of unified federal registration base for taxpayers’ recording; openness and general availability of information about all taxpayers registered on the territory of Russia; wide list of services on state registration that are rendered by tax authorities to taxpayers; transition to the regime of “single window” in interaction between registering structures; prejudicial regulation of appeal of decisions on state registration of legal entities and individual entrepreneurs) and system problems (impossibility of use of unified registration number of a taxpayer for coordination of information about him in different state organizations; irrelevance and incompleteness of information contained in databases of different state institutions; conscious evasion of taxpayers of performance of tax obligations on registration; difficulty of timely detection of short-lived companies; significant volume of migrant organizations; insufficient technical and program support of regional tax inspections) linked to registration processes are elicited.peer-reviewe