arXiv subjects

A. A. Sorokin

Publications and source records attributed to A. A. Sorokin.

9 recordsLinked to original sources

arXiv2025

Ultrafast solid-state chemical synthesis of BaTiO3 initiated by gyrotron microwave radiation

This work presents the results of a study on the solid-state synthesis of barium titanate under continuous microwave radiation from a 24 GHz gyrotron in a multimode cavity reactor. It is shown that in localized domains where fine-scale thermal instabilities develop, initiated by microwave radiation within the initial stoichiometric reaction mixture of ultrafine barium carbonate and titanium dioxide powders, the synthesis can proceed within 1,5 - 7 minutes, achieving a target product yield of up to 90%. Based on a developed realistic numerical model of the multimode reactor, involving an iterative solution of stationary Maxwell and heat conduction equations, it is demonstrated that the specific absorbed power in the domains where fine-scale thermal instabilities develop can reach 670 W/cm3 under an input microwave power of 400 W.

cond-mat.mtrl-sci↗

arXiv2023

Quantum squeezing via self-induced transparency in a photonic crystal fiber

We study the quantum squeezing produced in self-induced transparency in a photonic crystal fiber by performing a fully quantum simulation based on the positive $P$ representation. The amplitude squeezing depends on the area of the initial pulse: when the area is $2π$, there is no energy absorption and no amplitude squeezing. However, when the area is between 2$π$ and 3$π$, one observes amplitude-dependent energy absorption and a significant amount of squeezing. We also investigate the effect of damping and temperature: the results indicate that a heightened atom-pulse coupling, caused by an increase in the spontaneous emission ratio reduces the amplitude squeezing.

quant-ph↗

arXiv2023

A New View on the Application of Gold Nanoparticles in Cancer Therapy

In biomedical research and the practice of cancer therapy, gold nanoparticles have been used to visualize malignant tumors, as the heated bodies for hyperthermia of cancer cells, as drug carriers to deliver drugs to a cancer cell, but, to the best of our knowledge, they have not yet been used consciously as the sources of terahertz (THz) radiation delivered to a cancer cell that contributes to the inhibition of cell activity. It is predicted here that gold nanoparticles less than 8 nm in size are sources of spontaneous THz radiation, and the possibility of their application in oncology is due to the known effects of THz radiation on the cells of living organisms. There are indications that nanoparticles with a size comparable to the width of the major groove of the DNA molecule will be the most effective. Another effect that has not yet been taken into account in biomedical studies using gold nanoparticles is that of local electric fields due to the contact potential difference above edges and vertices of gold nanoclusters. The prerequisites and possibilities for searching for the manifestations of these two effects when gold nanoparticles are introduced into living cells of organisms are considered.

physics.med-ph↗

arXiv2023

Optimizing the generation of polarization squeezed light in nonlinear optical fibers driven by femtosecond pulses

Bright squeezed light can be generated in optical fibers utilizing the Kerr effect for ultrashort laser pulses. However, pulse propagation in a fiber is subject to nonconservative effects that deteriorate the squeezing. Here, we analyze two-mode polarization squeezing, which is SU(2)-invariant, robust against technical perturbations, and can be generated in a polarization-maintaining fiber. We perform a rigorous numerical optimization of the process and the pulse parameters using our advanced model of quantum pulse evolution in the fiber that includes various nonconservative effects and real fiber data. Numerical results are consistent with experimental results.

quant-ph↗

arXiv2022

Comparison of Three Job Mapping Algorithms for Supercomputer Resource Managers

Performance of supercomputer depends on the quality of resource manager, one of its functions is assignment of jobs to the nodes of clusters or MPP computers. Parts of parallel programs interact with each other with different intensity, and mapping of program to supercomputer nodes influence efficiency of the run. At each program run graph representing application program is to be mapped onto graph of nodes representing a subset of computer system. The both graphs are not known beforehand, hence the mapping must be done in reasonable time while scheduling resources. Three mapping algorithms were explored: parallel versions of simulated annealing, genetic and composite algorithms. A set of experimental runs with different algorithms parameters was performed, comparison of mapping quality and runtime was made, and suggestions on applicability of algorithms for resource managers were provided.

cs.PF↗

arXiv2020

On the possibility of research the photon-photon interaction at the European X-ray Free Electron Laser -- European XFEL

The possibility of performing the experimental research in the field of fundamental physics based on the unique instrument -- European X-ray Free Electron Laser (E-XFEL) is considered in this paper. The calculations of the reaction $γ+ γ\to e^{+} + e^{-}$ cross section for gamma quanta with $E \sim~(1-100)\,\mbox{GeV}$ energy with X-ray photons are performed. The possibility of experimental registration of reaction $γ+ γ\to e^{+} + e^{-}$ product are reviewed. Also, the optical depth of the interaction between gamma-rays with the E-XFEL's photon pulses is estimated. Astrophysical applications are discussed.

hep-ex↗

arXiv2013

Electrostatic map of T7 DNA. Comparative analysis of functional and electrostatic properties of T7 RNA polymerase specific promoters

The entire T7 bacteriophage genome contains 39937 base pairs (Database NCBI RefSeq N1001604). Here, electrostatic potential distribution around double helical T7 DNA was calculated by Coulomb method using the computer program of Sorokin A.A. Electrostatic profiles of 17 promoters recognized by T7 phage specific RNA polymerase were analyzed. It was shown that electrostatic profiles of all T7 RNA polymerase specific promoters can be characterized by distinctive motifs which are specific for each promoter class. Comparative analysis of electrostatic profiles of native T7 promoters of different classes demonstrates that T7 RNA polymerase can differentiate them due to their electrostatic features.

q-bio.BM↗

arXiv2010

The gamma->alpha phase transition in cerium is not isostructural

Using a small amount of radioactive 111Cd atoms implanted in cerium lattice to probe the hyperfine electric quadrupole interaction, we have detected a quadrupole electron charge density component in alpha-Ce, which is absent in gamma-Ce. The appearance of the quadrupole density in alpha-Ce predicted by the quadrupole scenario of the phase transition demonstrates that the spacial symmetry is lowered at the gamma->alpha phase transition. This finding makes cerium the first element where the symmetry change is driven exclusively by the valence electron degrees of freedom while the atomic centers of mass (cerium nuclei) occupy the face centered cubic positions. We also report on nuclear quadrupole interactions in other high pressure phases of cerium: alpha' (C2/m space symmetry) and alpha' (alpha-U structure).

cond-mat.str-el↗

arXiv2007

111Cd- TDPAC study of pressure-induced valence transition in YbAl2

The quadrupole interaction at 111Cd impurity nuclei in the intermediate-valence compound YbAl2 has been measured under pressure up to 80 kbar by the TDPAC spectroscopy. It was found that the quadrupole frequency nQ measured on the 111Cd located at the Al sites in YbAl2, varies nonlinearly and increases by almost four times with the pressure increase up to 80 kbar. A linear correlation between the mean Yb valence, derived from Yb L3 OFY-XAS and RXES measurements, and the electric field gradient (the quadrupole frequency nQ=eQVzz/h) has been observed. The quadrupole frequencies on 111Cd in the GdAl2, YbAl3, TmAl3 and CaAl2 compounds have been measured, also. The possibility of determining the valence of Yb in the Yb compounds with p-metals from the relation nQ (u(P)) = n2 + (n3 - n2) u(P) has been considered.

cond-mat.mtrl-sci↗