Interplay between Josephson and Aharonov-Bohm effects in Andreev interferometers
Proximity induced quantum coherence of electrons in multi-terminal voltage-driven hybrid normalsuperconducting
nanostructures may result in a non-trivial interplay between topology-dependent
Josephson and Aharonov-Bohm effects. We elucidate a trade-off between stimulation of the voltagedependent
Josephson current due to non-equilibrium effects and quantum dephasing of quasiparticles
causing reduction of both Josephson and Aharonov-Bohm currents. We also predict phase-shifted
quantum coherent oscillations of the induced electrostatic potential as a function of the externally
applied magnetic flux. Our results may be employed for engineering superconducting nanocircuits with
controlled quantum properties.
A three-parametrical family of ODEs on a torus arises from a model of Josephson effect in a resistive case when a Josephson junction is biased by a sinusoidal microwave current. We study asymptotics of Arnold tongues of this family on the parametric plane (the third parameter is fixed) and prove that the boundaries of the tongues are asymptotically close to Bessel functions.
We show that a weak external magneticfield affects significantly non-equilibrium quasiparticle (QP) distributions under the conditions of the inverse proximity effect using the single-electron hybrid turnstile as a generic example. Inverse proximity suppresses the superconducting gap in superconducting leads in the vicinity of turnstile junctions, thus trapping hot QPs in this region. An external magnetic field creates additional QP traps in the leads in the form of vortices or regions with a reduced superconducting gap resulting in the release of QPs away from junctions. We present a clear experimental evidence of the interplay of the inverse proximity effect and magnetic field revealing itself in the superconducting gap enhancement and significant improvement of the turnstile characteristics. The observed interplay and its theoretical explanation in the context of QP overheating are important for various superconducting and hybrid nanoelectronic devices, whichfind applications in quantum computation, photon detection and quantum metrology.
An analytic description of Aharonov – Bohm oscillation of the Coulomb potential of an immovable point charge in a magnetized Electronic gas of quantum cylinder is given.
Opal matrix is a regular 3D-packing of spherical particles of amorphous SiO2, forming an ordered system of voids. Opal matrixes with spherical particles of SiO2 diameter d ≈ 260 nm (Δd ≈ 2 %) were synthesized. The frequency dependences of the conductivity, real and imaginary components of the dielectric and magnetic conductivity of nanocomposites containing crystallites 16–65 nm in size of magnetic materials ‒ double phosphates (LiNiPO4, LiCoPO4) and vanadates (GdVO4 and DyVO4) were measured. The dielectric losses of nanocomposites remain low (at a level of ~ 0.06) in the frequency range 107–1010 Hz for nanocomposites with DyVO4 and LiCoPO4. The dielectric loss increases both in the direction of low frequencies (< 106 Hz) and in the direction of THz frequencies.
The materials of The International Scientific – Practical Conference is presented below.
The Conference reflects the modern state of innovation in education, science, industry and social-economic sphere, from the standpoint of introducing new information technologies.
It is interesting for a wide range of researchers, teachers, graduate students and professionals in the field of innovation and information technologies.
We have studied the effect of surface modification with acids and subsequent heat treatment on the properties of hydrous zirconia. It has been shown that surface modification with phosphate and sulfate groups makes it possible not only to control the phase composition of the heat-treated oxide but also to considerably suppress particle growth. We have discussed the processes involved and shown that, in the initial stages of thermolysis, the process leads to the formation of metastable, tetragonal ZrO2, which transforms into monoclinic zirconia at higher temperatures. Surface modification with phosphoric acid stabilizes tetragonal zirconia up to 850°C.
This volume contains the papers presented at the session "Data Science" within the V International Conference on Information Technology and Nanotechnology (ITNT-2019). The conference was held in Samara, Russia, during May 21-24, 2019 (itnt-conf.org). The conference is a forum for leading researchers from all over the world aimed to discuss the latest advances in the basic and applied research in the field of Information Technology and Nanotechnology. It is also aimed to attract young people to advanced scientific research and share the latest trends in training and research programs for future ITNT specialists . In addition to the session "Data Science", ITNT-2019 also included three other sessions: "Computer Optics and Nanophotonics", "Image Processing and Earth Remote Sensing" and "Mathematical Modeling of Physico-Technical Processes and Systems". The whole forum brought together more than 450 scientists from United Kindom, Japan, Switzerland, Iran, Poland, Bulgaria, Finland, China, Kazakhstan and Russia, as well as representatives of global high-tech corporations, developers of modern electronics – Huawei, Nvidia, Intel, and Azimuth Photonics, and more than 60 cities in the world. 436 talks enabled discussion on a wide range of topics. The topics of the session "Data Science" were grouped into the following key directions: Data Mining (Big data, Systems and platforms, Methods); Machine Learning (Neural networks, Statistical methods, Feature-based classification, Applications); Security, Cryptography (Cryptosystems design and analysis, Mathematical and algorithmic aspects, Efficient implementations of algorithms, Network security); High Performance Computing (Parallel programming models and languages, Highperformance implementations, Complex systems simulation).
A number of MK-40 cation-exchange membrane samples modified with ceria have been obtained. The membranes have been studied using a set physicochemical methods, including impedance spectroscopy, scanning electron microscopy, microanalysis, transmission electron microscopy, and XRD phase analysis. Ithas been shown that the embedding of cerium oxide reduces the humidity content and ionic conduction of membranes. It is accompanied by a marked increase in the membrane selectivity expressed by a decrease in transfer numbers with respect to anions
This volume presents new results in the study and optimization of information transmission models in telecommunication networks using different approaches, mainly based on theiries of queueing systems and queueing networks .
The paper provides a number of proposed draft operational guidelines for technology measurement and includes a number of tentative technology definitions to be used for statistical purposes, principles for identification and classification of potentially growing technology areas, suggestions on the survey strategies and indicators. These are the key components of an internationally harmonized framework for collecting and interpreting technology data that would need to be further developed through a broader consultation process. A summary of definitions of technology already available in OECD manuals and the stocktaking results are provided in the Annex section.