Quantum Maps with Memory from Generalized Lindblad Equation

In this paper, we proposed the exactly solvable model of non-Markovian dynamics of open quantum systems. This model describes open quantum systems with memory and periodic sequence of kicks by environment. To describe these systems, the Lindblad equation for quantum observable is generalized by taking into account power-law fading memory. Dynamics of open quantum systems with power-law memory are considered. The proposed generalized Lindblad equations describe non-Markovian quantum dynamics. The quantum dynamics with power-law memory are described by using integrations and differentiation of non-integer orders, as well as fractional calculus. An example of a quantum oscillator with linear friction and power-law memory is considered. In this paper, discrete-time quantum maps with memory, which are derived from generalized Lindblad equations without any approximations, are suggested. These maps exactly correspond to the generalized Lindblad equations, which are fractional differential equations with the Caputo derivatives of non-integer orders and periodic sequence of kicks that are represented by the Dirac delta-functions. The solution of these equations for coordinates and momenta are derived. The solutions of the generalized Lindblad equations for coordinate and momentum operators are obtained for open quantum systems with memory and kicks. Using these solutions, linear and nonlinear quantum discrete-time maps are derived.     

Development of Josephson Traveling-Wave Parametric Amplifier Based on Aluminum SIS Junctions

Physics of the Solid State - Prototypes of the design of Josephson traveling-wave parametric amplifier based on aluminum superconductor–insulator–superconductor junctions in the form of...     

Observation of electric quadrupole spin resonance of Ho<Superscript>3+</Superscript> impurity ions in synthetic forsterite

The anomalous dependence of the electron paramagnetic resonance (EPR) line shape on the microwave power in the resonator has been found when studying the continuous-wave EPR spectra of impurity holmium ions in synthetic forsterite on an ELEXSYS E 580 EPR spectrometer. The power-threshold transition from the conventional lines being the derivatives of the spectral line contours to the spectral line contours themselves has been observed as the power increased. The properties of the anomalous EPR lines are qualitatively explained assuming that the resonance electric quadrupole transitions take place between the electron spin levels.     

A wet chemical preparation of transparent conducting thin films of Al-doped ZnO nanoparticles

A wet chemical deposition method for preparing transparent conductive thin films on the base of Al-doped ZnO (AZO) nanoparticles has been demonstrated. AZO nanoparticles with a size of 7 nm have been synthesised by a simple precipitation method in refluxed conditions in ethanol using zinc acetate and Al-isopropylate. The presence of Al in ZnO was revealed by the EDX elemental analysis (1.8 at.%) and UV–Vis spectroscopy (a blue shift due to Burstein–Moss effect). The obtained colloid solution with the AZO nanoparticles was used for preparing by spin-coating thin films on glass substrates. The film demonstrated excellent homogeneity and transparency (T > 90%) in the visible spectrum after heating at 400 °C. Its resistivity turned to be excessively high (ρ = 2.6 Ω cm) that we ascribe to a poor charge percolation due to a high film porosity revealed by SEM observations. To improve the percolation via reducing the porosity, a sol–gel solution was deposited “layer-by-layer” in alternation with layers derived from the AZO colloid followed by heating. As it was shown by optical spectroscopy measurements, the density of thus prepared film was increased more than twice leading to a significant decrease in resistivity to 1.3 × 10⁻² Ω cm.     

NMR studies of the structure of polytetra-fluoroethylene- and ammonium fluorosilicate-based composites

NMR spectroscopy is used to study the structural features of polymer composites produced by the simultaneous pyrolysis of a polytetrafluoroethylene and ammonium fluorosilicate mixture. The effect is discussed of technological factors on the composition and structure of fluoropolymer composites.     

Quick ellipsometric technique for determining the thicknesses and optical constant profiles of Fe/SiO2/Si(100) nanostructures during growth

An algorithm is developed to perform rapid control of the thickness and optical constants of a film structure during growth. This algorithm is tested on Fe/SiO₂/Si(100) structures grown in an Angara molecular-beam epitaxy setup. The film thicknesses determined during their growth are compared with X-ray spectral fluorescence analysis and transmission electron microscopy data.     

Computer-aided designing of simple electron-optical systems for electron image tubes

We consider the possibility of designing time-analyzing electron-optical systems for electron image tubes with subpicosecond resolution, containing no spherical electrodes, fine-structure grids, or narrow slots (i.e., extremely simple systems with high spatial and temporal resolutions).     

Synthesis of carbon nanofibers by catalytic pyrolysis of ethylene and methane on hydrides of intermetallic compounds of lanthanum with nickel

Carbon nanofibers were synthesized by the pyrolysis of ethylene and methane on hydrides of intermetallides LaNi_nH_x (n = 2, 3, 5; x = 0.1–4). The influence of parameters of the synthesis (temperature and the ratio of gases in an Ar: H₂: C₂H₄ (CH₄) mixture) on the structure of nanofibers thus formed was studied. Hydrides of nickel intermetallides are more efficient catalytic systems than metallic nickel. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2210–2214, October, 2005.     

Quantum dissipative systems. I. Canonical quantization and quantum Liouville equation

Sedov's variational principle, which is a generalization of the principle of least action to dissipative processes, is used to generalize canonical quantization and the von Neumann equations to dissipative systems. The example of a harmonic oscillator with friction is considered.Institute of Nuclear Physics, State University, Moscow. Translated from Teoreticheskaya i Matematicheskaya Fizika Vol. 100, No. 3, pp. 402–417, September, 1994.