Turbulence in Binary Bose-Einstein Condensates Generated by Highly Non-Linear Rayleigh-Taylor and Kelvin-Helmholtz Instabilities

Quantum turbulence (QT) generated by the Rayleigh-Taylor instability in binary immiscible ultracold 87Rb atoms at zero temperature is studied theoretically. We show that the quantum vortex tangle is qualitatively different from previously considered superfluids, which reveals deep relations between QT and classical turbulence. The present QT may be generated at arbitrarily small Mach numbers, which is a unique property not found in previously studied superfluids. By numerical solution of the coupled Gross-Pitaevskii equations we find that the Kolmogorov scaling law holds for the incompressible kinetic energy. We demonstrate that the phenomenon may be observed in the laboratory.Comment: Revised version. 7 pages, 8 figure

Analysis of Physical Readiness of First Course Students after Self-Isolation

В статье представлены результаты исследования физической подготовленности студентов транспортного вуза после вынужденной самоизоляции. Установлено, что у большинства студентов первого курса самые низкие показатели отмечаются в силовых характеристиках плечевого пояса и работоспособности сердечно-сосудистой системы, а именно эти показатели являются профессионально значимыми в будущей профессиональной деятельности специалиста железной дороги. Правильно подобранные комплексы упражнений с учетом индивидуальных физических нагрузок смогут обеспечить оптимальный двигательный режим и внести коррекцию в кондиционную подготовленность студента

Synthesis, Structure, and Magnetic Properties of an Al2O3/Ge-p/Al2O3/Co Thin-Film System

Abstract—Structural and magnetic measurements are made of an Al2O3/Ge-p/Al2O3/Co thin-film system. The structure is synthesized via ion-plasma deposition and can be used as a tunnel heterostructure. The dependences of the magnetic properties of cobalt on the rate of its deposition and the rates of deposition of preceding layers are established

Parametric resonance of capillary waves at the interface between two immiscible Bose-Einstein condensates

We study parametric resonance of capillary waves on the interface between two immiscible Bose-Einstein condensates pushed towards each other by an oscillating force. Guided by analytical models, we solve numerically the coupled Gross-Pitaevskii equations for two-component Bose-Einstein condensate at zero temperature. We show that, at moderate amplitudes of the driving force, the instability is stabilized due to non-linear modifications of the oscillation frequency. When the amplitude of the driving force is large enough, we observe detachment of droplets from the Bose-Einstein condensates, resulting in generation of quantum vortices (skyrmions). We analytically investigate the vortex dynamics, and conditions of quantized vortex generation.Comment: (Version 2) 11 resized figures. One new reference adde

Interface dynamics of a two-component Bose-Einstein condensate driven by an external force

The dynamics of an interface in a two-component Bose-Einstein condensate driven by a spatially uniform time-dependent force is studied. Starting from the Gross-Pitaevskii Lagrangian, the dispersion relation for linear waves and instabilities at the interface is derived by means of a variational approach. A number of diverse dynamical effects for different types of the driving force is demonstrated, which includes the Rayleigh-Taylor instability for a constant force, the Richtmyer-Meshkov instability for a pulse force, dynamic stabilization of the Rayleigh-Taylor instability and onset of the parametric instability for an oscillating force. Gaussian Markovian and non-Markovian stochastic forces are also considered. It is found that the Markovian stochastic force does not produce any average effect on the dynamics of the interface, while the non-Markovian force leads to exponential perturbation growth.Comment: 13 pages, 12 figure

Decoherence of Bose-Einstein condensates in microtraps

We discuss the impact of thermally excited near fields on the coherent expansion of a condensate in a miniaturized electromagnetic trap. Monte Carlo simulations are compared with a kinetic two-component theory and indicate that atom interactions can slow down decoherence. This is explained by a simple theory in terms of the condensate dynamic structure factor.Comment: 5 pages, 4 figure

Parametric localized modes in quadratic nonlinear photonic structures

We analyze two-color spatially localized modes formed by parametrically coupled fundamental and second-harmonic fields excited at quadratic (or chi-2) nonlinear interfaces embedded into a linear layered structure --- a quasi-one-dimensional quadratic nonlinear photonic crystal. For a periodic lattice of nonlinear interfaces, we derive an effective discrete model for the amplitudes of the fundamental and second-harmonic waves at the interfaces (the so-called discrete chi-2 equations), and find, numerically and analytically, the spatially localized solutions --- discrete gap solitons. For a single nonlinear interface in a linear superlattice, we study the properties of two-color localized modes, and describe both similarities and differences with quadratic solitons in homogeneous media.Comment: 9 pages, 8 figure

Взаимосвязь аргирофильных белков ядрышкообразующих районов и антигена ki-67 с клинико-морфологическими параметрами и выживаемостью при аденокарциноме легкого

Argyrophilic proteins associated with nucleolar organizer regions (Ag-NOR proteins) and Ki-67 antigen were investigated in patients with lung adenocarcinoma. Tumors with low and high content of Ag-NOR proteins and proliferation index (PI) Ki-67 were determined. The relationship between the Ag-NOR content and T and N parameters, tumor size of 3 cm or more and stage of the disease was found. High survival rates in patients with lung adenocarcinoma were associated with the low content of Ag-NOR proteins and PI Ki-67 and low survival rates were related to the high content of Ag-NOR proteins and PI Ki-67. The intermediate survival rates were related to the opposite values of the content of Ag-NOR proteins and PI Ki-67. The tumor size, N parameter and the content of Ag-NOR proteins had an independent effect on survival of patients. Survival was related to the size of the tumor in lung cancer patients having no lymph node involvement and it was related to the content of Ag-NOR proteins in cases with the presence of metastases. Mutual study of Ag-NOR proteins and antigen Ki-67 has differential diagnostic and prognostic value in lung adenocarcinoma.Исследованы аргирофильные белки, ассоциированные с ядрышкообразующими районами (Ag-ЯОР-белки) и антиген Ki-67 в аденокарциноме легкого. Определяли опухоли с низким и высоким содержанием Ag-ЯОР-белков и индекса метки (ИМ) Ki-67. Содержание Ag-ЯОР-белков имело связь с показателями Т, N, размером опухоли до 3 см и более, стадией заболевания. Выжи- ваемость больных аденокарциномой легкого лучше при опухолях с низким содержанием Ag-ЯОР-белков или ИМ Ki-67. Высокая выживаемость связана с низким содержанием Ag-ЯОР-белков и ИМ Ki-67, низкая – с высоким содержание Ag-ЯОР-белков и ИМ Ki-67, промежуточная – с противоположными значениями содержания Ag-ЯОР-белков и ИМ Ki-67. Размер опухоли, показатель N и содержание Ag-ЯОР-белков имели независимое влияние на прогноз выживаемости больных. При аденокарциноме легкого без метастазов в лимфатические узлы выживаемость связана с размером опухоли, при наличии метастазов – с содержанием Ag-ЯОР- белков. Взаимное исследование Ag-ЯОР-белков и антигена Ki-67 имеет дифференциально-диагностическое и прогностическое значение при аденокарциноме легкого