Spin Filtering via Resonant Reflection of Relativistic Surface States

A microscopic approach is developed to scattering of surface states from a non-magnetic linear defect at a surface with strong spin-orbit interaction. Spin-selective reflection resonances in scattering of Rashba-split surface states by an atomic stripe are theoretically discovered in a proof-of-principle calculation for a model crystal potential. Spin-filtering properties of such linear defects are analyzed within an envelope-function formalism for a perturbed surface based on the Rashba Hamiltonian. The continuous Rashba model is found to be in full accord with the microscopic theory, which reveals the essential physics behind the scattering resonance. The spin-dependent reflection suggests a novel mechanism to manipulate spins on the nanoscale.Comment: 6 pages, 4 figures, 1 tabl

Towards a theory of attosecond transient recorder

Laser assisted photoemission by a chirped subfemtosecond extreme ultraviolet (XUV) pulse is considered within an exactly solvable quantum-mechanical model. Special emphasis is given to the energy dependence of photoexcitation cross-section. The streaked spectra are analyzed within the classical picture of initial time-momentum distribution r_ini(p,t) of photoelectrons mapped to the final energy scale. The actual time-momentum distribution in the absence of the probe laser field is shown to be a poor choice for r_ini, and a more adequate ansatz is suggested. The semiclassical theory offers a simple practically useful approximation for streaked spectra. Its limitations for sufficiently long chirped XUV pulses are established.Comment: 9 pages 8 figure

Assessment of the Impact of Aggregated Economic Factors on Optimal Consumption in Models of Economic Growth

The problem of consumption-optimal economic growth is considered. In the model there are three factors of production: capital, labor and useful work, that interact in the production of homogenous output. At any instant of time a fraction of this homogeneous output can be allocated to investment in accumulation of capital and useful work. The gross domestic product (GDP) of a country is presented by the linear-exponential (LINEX) production function. The general goals of the research can be formulated as follows: -analysis of properties of the LINEX production function and identification of parameters under restrictions on elasticity coefficients; -analysis of the Hamiltonian system of differential equations for the Pontryagin maximum principle in the optimal control problem; -elaboration of an algorithm for constructing synthetic trajectories of optimal economic growth; -development of software for numerical simulation and sensitivity analysis; -comparison of real and synthetic trajectories of economic growth, and simulation of future scenarios

Stable Mutual Tracking Block for a Real Dynamical Object and a Virtual Model-Leader

The work is devoted to the problem of stochastic stable mutual tracking of motions of the real dynamical x-object and the somewhat virtual z-model under the dynamical and informational disturbances. The elaborated algorithms are applied to some differential games on minimax and maximin for the positional quality index of the control process. Results of computer simulation of model problems are presented