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

Гармонический анализатор спектра

Запропоновано схему гармонійного аналізатора спектра для апаратурної реалізації прямого перетворення Фур’є з високою швидкодією та малою потужністю споживання.The circuit of the harmonious analyzer of a spectrum for hardware realization of direct transformation Fur'e with high speed and low power of consumption is offered.Предложена схема гармонического анализатора спектра для аппаратурной реализации прямого преобразования Фурье с высоким быстродействием и малой мощностью потребления

Rare earth spin ensemble magnetically coupled to a superconducting resonator

Interfacing superconducting quantum processors, working in the GHz frequency range, with optical quantum networks and atomic qubits is a challenging task for the implementation of distributed quantum information processing as well as for quantum communication. Using spin ensembles of rare earth ions provide an excellent opportunity to bridge microwave and optical domains at the quantum level. In this letter, we demonstrate magnetic coupling of Er$^{3+}$ spins doped in Y$_{2}$SiO$_{5}$ crystal to a high-Q coplanar superconducting resonator.Comment: 5 pages, 3 figure

Физическая научно-техническая модель исследования микроконтроллеров

В даній роботі запропонована фізична науково-технічна модель ефективного дослідження мікроконтролерів (МК), яка забезпечує якісне розв’язання локальних задач при застосуванні відповідної мікропроцесорної системи керування в проблемно-орієнтованих системах. Проведено системний аналіз основних технічних параметрів множини моделей сучасних МК; визначено фізичне моделювання, розроблені критерії подібності за багатьма визначальними величинами, на базі властивостей теорії неповної подібності та розмірностей. Побудована багатокритеріальна знакова модель в безрозмірних координатах, візуалізація якої дозволяє швидко визначити тип МК, характеристики якого відповідають вимогам замовника. Розроблена та побудована фізична науково-технічна модель за допомогою запропонованої моделі електричної принципової схеми МК, розроблених моделей лістингу програм керування, завдяки яким візуалізація динаміки процесу забезпечується як на моніторі ноутбука, так і за допомогою яскравості вбудованого світлодіоду.In this paper the physical scientific technical model is described, which is used for the modern microcontrollers study. Based on a systematic analysis of microcontrollers amount and on the offered method for determining the required model on customer’s parameters, the choice of microcontroller is made, which complies with the requirements customer. The symbolic model of technical parameters dependencies of the MC in dimensionless coordinates is built, and the model for setting to the computer is worked out; a program listing for the firmware of the microcontroller is developed; a physical model is created, which provides wide opportunities for providing the dynamic parameters of microcontrollers research. The research on influence on changes in the values of the time parameters for LEDs brightness is conducted.В данной работе предложена физическая научно-техническая модель эффективного исследования микроконтроллеров (МК), которая обеспечивает качественное решение локальных задач при применении соответствующей микропроцессорной системы управления в проблемно-ориентированных системах. Проведен системный анализ основных технических параметров множества моделей современных МК; определено физическое моделирование, разработаны критерии подобия по многим определяющими величинами, на базе теории неполного подобия и размерностей. Построена многокритериальная знаковая модель в безразмерных координатах, визуализация которой позволяет быстро определить тип МК, который соответствует требованиям заказчика. Разработана и построена физическая научно-техническая модель с помощью предложенной модели электрической принципиальной схемы МК, разработанных моделей листинга программ управления, благодаря которым визуализация динамики процесса обеспечивается как на мониторе ноутбука, так и с помощью яркости встроенного светодиода

A method of reconstruction after pancreaticoduodenectomy for pancreatic malignancies in very young children: Two cases reports

Pancreatic tumors are very rare diseases in very young children. Most information about those diseases in children was published in cases reports. Due to the rare nature of pancreatic tumors in children, there remains the absence of diagnostic algorithms, clear radiographic and morphological assessments as well as evidence based best treatment options. Because of the young age of patients and the rare occurrence of pancreatic neoplasms, tumor detection remains poor. For malignancies affecting the head of the pancreas the only possibility for achieving clear surgical margins is performing a pancreaticoduodenectomy (PD). We describe two cases of diagnostic and treatment of pancreatic tumor of very young children what was done in our institute

Coherent oscillations in a superconducting tunable flux qubit manipulated without microwaves

We experimentally demonstrate the coherent oscillations of a tunable superconducting flux qubit by manipulating its energy potential with a nanosecond-long pulse of magnetic flux. The occupation probabilities of two persistent current states oscillate at a frequency ranging from 6 GHz to 21 GHz, tunable via the amplitude of the flux pulse. The demonstrated operation mode allows to realize quantum gates which take less than 100 ps time and are thus much faster compared to other superconducting qubits. An other advantage of this type of qubit is its insensitivity to both thermal and magnetic field fluctuations.Comment: 5 pages, 5 figure

Laser Scanning Microscopy of HTS Films and Devices

The work describes the capabilities of Laser Scanning Microscopy (LSM) as a spatially resolved method of testing high_Tc materials and devices. The earlier results obtained by the authors are briefly reviewed. Some novel applications of the LSM are illustrated, including imaging the HTS responses in rf mode, probing the superconducting properties of HTS single crystals, development of twobeam laser scanning microscopy. The existence of the phase slip lines mechanism of resistivity in HTS materials is proven by LSM imaging.Comment: 17 pages, 21 figures, Submitted to Fizika Nizkikh Temperatur (Low Temperature Physics

Imaging the Anisotropic Nonlinear Meissner Effect in Nodal YBa2_{2}Cu3_{3}O7−δ_{7-\delta} Thin-Film Superconductors

We have directly imaged the anisotropic nonlinear Meissner effect in an unconventional superconductor through the nonlinear electrodynamic response of both (bulk) gap nodes and (surface) Andreev bound states. A superconducting thin film is patterned into a compact self-resonant spiral structure, excited near resonance in the radio-frequency range, and scanned with a focused laser beam perturbation. At low temperatures, direction-dependent nonlinearities in the reactive and resistive properties of the resonator create photoresponse that maps out the directions of nodes, or of bound states associated with these nodes, on the Fermi surface of the superconductor. The method is demonstrated on the nodal superconductor YBa$_{2}$Cu$_{3}$O$_{7-\delta}$ and the results are consistent with theoretical predictions for the bulk and surface contributions.Comment: 5 pages, 3 figures, Phys. Rev. Lett. (in press

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