Alexander V. Bogdanov

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A monolithically integrated asymmetric graded index (GRIN) or step-index (GRIN) mode converters for microphotonic waveguides are proposed and described. The design parameters and tolerances are calculated for amorphous silicon (a-Si) couplers integrated with silicon-on-insulator waveguides. The GRIN and step-index couplers operate over a wide wavelength(More)
Simulation of beam dynamics is an important step needed to aid the design and configuration of particle beam accelerators. A number of methods and software packages have been developed to address modeling in accelerator physics. However, the results of simulations often need to be validated by simultaneous usage of several packages for solving similar(More)
The system of oscillator interacting with vacuum is considered as a problem of random motion of quantum reactive harmonic oscillator (QRHO). It is formulated in terms of a wave functional regarded as complex probability process Ψstc (x, t | W (t)) in the extended space Ξ = R⊗R{W (t)}. This wave functional obeys some stochastic differential equation (SDE).(More)
Solid solution perovskite Pb(Zr1-xTix)O3 (PZT) is an industrially important material. Despite the long history of experimental and theoretical studies, the structure of this material is still under intensive discussion. In this work, we have applied structure searching coupled with density functional theory methods to provide a multiphase description of(More)
The problem of random motion of 1D quantum reactive harmonic oscillator (QRHO) is formulated in terms of a wave functional regarded as a complex probability process Ψstc (x, t; {ξ}) in an extended space Ξ = R ⊗ R{ξ}. In the complex stochastic differential equation (SDE) for Ψstc (x, t; {ξ}) the variables are separated with the help of the Langevin-type(More)
Networking is known to be a "bottleneck" in scientific computations on HPC clusters. It could become a problem that limits the scalability of systems with a cluster architecture. And that problem is a worldwide one since clusters are used almost everywhere. Expensive clusters usually have some custom networks. Such systems imply expensive and powerful(More)