A tunable rf SQUID manipulated as flux and phase qubit

We report on two different manipulation procedures of a tunable rf SQUID. First, we operate this system as a flux qubit, where the coherent evolution between the two flux states is induced by a rapid change of the energy potential, turning it from a double well into a single well. The measured coherent Larmor-like oscillation of the retrapping probability in one of the wells has a frequency ranging from 6 to 20 GHz, with a theoretically expected upper limit of 40 GHz. Furthermore, here we also report a manipulation of the same device as a phase qubit. In the phase regime, the manipulation of the energy states is realized by applying a resonant microwave drive. In spite of the conceptual difference between these two manipulation procedures, the measured decay times of Larmor oscillation and microwave-driven Rabi oscillation are rather similar. Due to the higher frequency of the Larmor oscillations, the microwave-free qubit manipulation allows for much faster coherent operations.Comment: Proceedings of Nobel Symposium "Qubits for future quantum computers", Goeteborg, Sweden, May 25-28, 2009; to appear in Physica Script

High resolution measurements of the switching current in a Josephson tunnel junction: Thermal activation and macroscopic quantum tunneling

We have developed a scheme for a high resolution measurement of the switching current distribution of a current biased Josephson tunnel junction using a timing technique. The measurement setup is implemented such that the digital control and read-out electronics are optically decoupled from the analog bias electronics attached to the sample. We have successfully used this technique to measure the thermal activation and the macroscopic quantum tunneling of the phase in a small Josephson tunnel junction with a high experimental resolution. This technique may be employed to characterize current-biased Josephson tunnel junctions for applications in quantum information processing.Comment: 10 pages, 8 figures, 1 tabl

The Modern World Landscape of Data Science Online Education

Data science as an emerging branch of applied knowledge and a new field of study is showing a strong momentum. Besides, the corresponding sphere of educational research is actively developing. At the same time, most of the scientific publications are aimed at studying specific issues related to the content of the programs and their methodological support. The wider context and especially the international perspective are lacking for the necessary attention of researchers.In this regard, the purpose of our study was to summarize and systematize information about training programs in the field of data science presented on online platforms of the main macro-regions – America, Europe and Asia. For this purpose, we found out what elements the corpus of data science training programs consists of, as well as how courses are distributed on educational platforms by countries, organizational providers, level of education and duration of study. Based on the data obtained, we conducted a comparative interregional study of educational programs presented on online platforms.The findings made it possible to draw conclusions about the specifics of the global landscape of data science online education, as well as to determine the specifics of the Russian segment and to formulate recommendations for solving significant problems of the domestic economy using data science online education

The Journal “Higher Education in Russia”: 30 Years of Research and Reflection

The round-table discussion dedicated to the 30th anniversary of the journal Vysshee obrazovanie v Rossii (Higher Education in Russia) took place on October 26, 2022 within the framework of XIII International conference of higher education (ICHE). Since its founding, the journal acts as a platform to discuss the urgent issues of higher education. In different periods, the researchers discussed competence-based approach, Bologna process, online education, quality of higher education, educational policy, educational management, assessment of learning outcomes, training of highly skilled researchers and teaching personnel, digitalization of education and many others. Today higher education in Russia is at a turning point of its history. We should impartially evaluate the path traveled, what has been achieved and what are the consequences. A look at the past became the subject of the round-table discussion

Protolytic properties of some bis(dimethylaminomethyl)phenols in the presence of surfactants

Aggregation and protolytic properties of bis(dimethylaminomethyl)phenols containing methyl (HA) and nonyl (HL) substituents at the benzene ring are studied in aqueous solutions of isopropanol and various surfactants with potentiometric titration, tensiometry, and mathematical modeling of equilibria. Monomers, dimers, and tetramers of HA and HL are found. It is shown that the degree of compound aggregation depends on the solution concentration and pH. Sodium dodecyl sulfate and HA form associates, whereas SDS and HL form mixed micelles at the CMC-1 and CMC-2 critical micellization concentrations. In micellar solutions of Triton X-100 and cetyltrimethylammonium bromide, the mixed micelles are not found via tensiometry. Protonated species of tetramer, dimer, and monomer of investigated compounds are revealed, depending on the acidity of the medium. Phenolate forms of HA and HL do not exist under experimental conditions. Apparent protonation constants are determined and it is shown that, for the HA compound that does not form micelles, the protonation constants of the same-type species increase in the presence of the three surfactants used as compared to the water-isopropanol solution. Decreasing constants of analogous HL forms in the solutions of CTAB, nonionic surfactant (C Tx = 10 mM), and SDS (pH > 7) are attributed to the formation of associates or mixed micelles of this compound and surfactants under experimental conditions. © Nauka/Interperiodica 2006

Properties of N,N-dimethyl-N′-(2-hydroxybenzyl)ethylenediamine as a ligand to copper(II)

The acid-basic and complexing properties of N,N-dimethyl-N′-(2- hydroxybenzyl)ethylenediamine (HL) in aqueous propan-2-ol were characterized by spectrophotometry, pH-metry, and mathematical simulation of equilibria in solutions (T = 25 ± 0.1°C, μ = 0.1 M KNO 3). Dimer H 2L 2 was found to predominate in solution at c HL = 0.01 mol/l. Three protonated dimeric (H 3L 2 +, H 4L 2 2+, and H 5L 2 3+), diprotonated monomeric (H 3L 2+), and triprotonated tetrameric forms (H 7L 4 3+) were detected in the system, depending on pH. At lower ligand concentrations (c HL = 0.0015 mol/l), the solution contains both dimers and monomers of this compound. The higher dentate number of HL compared to 2-alkylaminomethylphenols allows it to form more number of both mono- and binuclear complexes ([Cu(HL)] 2+, [Cu(HL) 2] 2+, [CuL 2], [CuL 2OH] -, [Cu 2(HL) 2] 4+, and [Cu 2(HL) 2L 2] 2+), making them more stable

Complexation of 1-hexadecyl-4-aza-1-azoniabicyclo[2.2.2]octane bromide with nickel nitrate in acetone

© 2016, Pleiades Publishing, Ltd.The complexation of 1-hexadecyl-4-aza-1-azoniabicyclo[2.2.2]octane bromide with Ni(II) nitrate in acetone is studied by means of spectrophotometry (the Job–Ostromisslensky technique and molar ratios). The formation of 3: 1 and 1: 1 ligand: metal complexes is established and confirmed by mathematical modeling. The stability constants of the complexes and the change in the Gibbs free energy are determined