Autoresonant excitation of Bose-Einstein condensates

Controlling the state of a Bose-Einstein condensate driven by a chirped frequency perturbation in a one-dimensional anharmonic trapping potential is discussed. By identifying four characteristic time scales in this chirped-driven problem, three dimensionless parameters $P_{1,2,3}$ are defined describing the driving strength, the anharmonicity of the trapping potential, and the strength of the particles interaction, respectively. As the driving frequency passes the linear resonance in the problem, and depending on the location in the $P_{1,2,3}$ parameter space, the system may exhibit two very different evolutions, i.e. the quantum energy ladder climbing (LC) and the classical autoresonance (AR). These regimes are analysed both in theory and simulations with the emphasis on the effect of the interaction parameter $P_{3}$. In particular, the transition thresholds on the driving parameter $P_{1}$ and their width in $P_{1}$ in both the AR and LC regimes are discussed. Different driving protocols are also illustrated, showing efficient control of excitation and de-excitation of the condensate

Resonant control of solitons

It is shown that the effect of "scattering on resonance" can be used to control envelope solitons in the driven nonlinear Schrödinger equation. The control occurs by the frequency modulated driving with multiple crossing of the resonant frequency of the soliton. Crown Copyright © 2013 Published by Elsevier B.V. All rights reserved

Micromagnetic modeling of autoresonance oscillations in yttrium-iron garnet films

One of the main problems of magnonics is finding the ways of efficiently spin waves excitation in a magnet. This paper considers the method of nonlinear amplification by phase locking of amplitude of dynamic magnetization in yttrium-iron garnet film performed by micromagnetic modeling with MuMAX3 software taking into account the real materials parameters. It is shown that the excited magnetization precession can be considered as a autoresonance phenomena. The intensity of the autoresonance in ferrimagnetic yttrium-iron garnet films has threshold dependence on the chirp rate of the exciting magnetic field. © Published under licence by IOP Publishing Ltd.Russian Foundation for Basic Research, RFBR: 19-32-90014Ural Branch, Russian Academy of Sciences, UB RAS: МК-4959.2018.2The work was carried out within the framework of the state assignment on the topic "Spin" №АААА-А18-118020290104-2, "Alloys" № АААА-А19-119070890020-3 and project №18-10-2-37 of the Program of the UB RAS, supported by Grant of the President of the Russian Federation № МК-4959.2018.2, also the reported study was funded by RFBR, project number 19-32-90014

Anomalous autoresonance threshold for chirped-driven Korteweg-de-Vries waves

Large amplitude traveling waves of the Korteweg-de-Vries (KdV) equation can be excited and controlled by a chirped frequency driving perturbation. The process involves capturing the wave into autoresonance (a continuous nonlinear synchronization) with the drive by passage through the linear resonance in the problem. The transition to autoresonance has a sharp threshold on the driving amplitude. In all previously studied autoresonant problems the threshold was found via a weakly nonlinear theory and scaled as α3/4,α being the driving frequency chirp rate. It is shown that this scaling is violated in a long wavelength KdV limit because of the increased role of the nonlinearity in the problem. A fully nonlinear theory describing the phenomenon and applicable to all wavelengths is developed. © 2015 American Physical Society

Luminescence of sapphire single crystals irradiated with high-power ion beams

Optical absorption, photo- and cathodoluminescence of a sapphire single crystal (α-Al 2 O 3 ) exposed to pulsed nanosecond radiation with high-power ion beams C + /H + with an energy of 300 keV and energy density 0.5-1.5 J/cm 2 were first investigated in this work. It was found that under ion irradiation accompanied by heating of sapphire up to melting, the formation of F-type centers and their aggregates associated with oxygen vacancies was observed in the crystals under study. These centers have luminescence bands at 330, 410 and 500 nm which depend on the type and wavelength of the optical excitation. The appearance of a new PL emission at 435 nm, presumably associated with a complex vacancy-impurity defect, was also observed in the photoluminescence spectra. © Published under licence by IOP Publishing Ltd.The work was supported by the initiative scientific project № 16.5186.2017/8.9 of the Ministry of Education and Science of the Russian Federation. Experiments on ion irradiation of sapphire was done at the KIPT as a part of the state task

Complete conversion between one and two photons in nonlinear waveguides: Theory of dispersion engineering

High-efficiency photon-pair production is a long-sought-after goal for many optical quantum technologies, and coherent photon conversion (CPC) processes are promising candidates for achieving this. We show theoretically how to control coherent conversion between a narrow-band pump photon and broadband photon pairs in nonlinear optical waveguides by tailoring frequency dispersion for broadband quantum frequency mixing. We reveal that complete deterministic conversion as well as pump-photon revival can be achieved at a finite propagation distance. We also find that high conversion efficiencies can be realised robustly over long propagation distances. These results demonstrate that dispersion engineering is a promising way to tune and optimise the CPC process. © 2022 The Author(s). Published by IOP Publishing Ltd on behalf of the Institute of Physics and Deutsche Physikalische Gesellschaft.Australian Research Council, ARC: DE180100070, DP160100619, DP190100277, FT170100399; Ministry of Education and Science of the Russian Federation, Minobrnauka: AAAA-A18-118020190095-4The authors acknowledge the support by the Australian Research Council (DE180100070, DP160100619, DP190100277). NKL is funded by the Australian Research Council Future Fellowship (FT170100399). Batalov S V acknowledges support by the Ministry of Education and Science of the Russian Federation (the theme ‘Quantum’, No. AAAA-A18-118020190095-4)

Takotsubo syndrome in a patient with atrial fibrillation after electrical cardioversion: a case report

The paper presents a description of the diagnosis and treatment of takotsubo syndrome in a patient with paroxysmal atrial fibrillation after electrical cardioversion. A case report clearly reflects the need for an integrated diagnostic approach to verify the diagnosis using dynamic echocardiography, electrocardiography, angiographic and tomographic investigations. The complexity of differential diagnosis in this case was an atypical variant of myocardial dysfunction. Follow-up made it possible to track the clinical improvement of the patient and the almost complete normalization of myocardial contractility in terms characteristic of takotsubo syndrome

Effect of catheter ablation for atrial fibrillation on left and right atrial function

Aim. To evaluate the effect of catheter ablation on left (LA) and right atria (RA) function in patients with atrial fibrillation.Material and methods. The study included 28 patients (14 men and 14 women) aged 33 to 72 years (mean age, 57,7±9,9 years) with paroxysmal (n=23) and persistent AF (n=5). All patients underwent radiofrequency ablation (RFA) with pulmonary vein antrum isolation. Before ablation and 3 days after, transthoracic twodimensional echocardiography was performed in sinus rhythm with an assessment of LA reservoir, conduit and booster pump function and RA peak longitudinal strain.Results. In the studied patients, a significant decrease in the reservoir, conduit and booster pump function of the LA was revealed after RFA, while there was no significant change in RA peak longitudinal strain after catheter ablation. LA reservoir, conduit and booster pump function decreased by 6,45% (p<0,001), 3,59% (p<0,001), 2,85% (p<0,001), respectively, while RA peak longitudinal strain increased by 0,73% (p=0,43).Conclusion. Catheter ablation has a significant damaging effect on the LA tissue, inhibiting the reservoir, pumping and pipeline functions. At the same time, the contractility of the PP in the early postoperative period improves, but not significantly

Influence of characteristics of epicardial adipose tissue and myocardial sympathetic innervation on the development of late recurrence of atrial fibrillation after radiofrequency ablation

Aim. To investigate the relationship between radiological characteristics of epicardial adipose tissue (EAT) and myocardial sympathetic activity, as well as to study their association with late recurrence of atrial fibrillation (AF) after radiofrequency ablation (RFA).Material and methods. This prospective study included 26 people with persistent and long-standing persistent AF scheduled for interventional AF treatment. Before the RFA procedure, all patients underwent cardiac 123I-metaiodobenzylguanidine (123I-MIBG) scintigraphy to assess the myocardial sympathetic innervation and contrast-enhanced cardiac multislice computed tomography to assess pulmonary vein anatomy, left atrial volume, and EAT volume. Clinical follow-up, including 12-lead electrocardiography (ECG) and 24-hour ECG monitoring, was carried out 3, 6 and 12 months after RFA.Results. After the end of follow-up, the patients were divided into two groups: with AF recurrence (group 1, n=8) and without AF recurrence (group 2, n=18). Multivariate logistic analysis found that only the 123I-MIBG washout rate (odds ratio, 1,0943; 95% confidence interval, 1,0138-1,1812) proved to be an independent predictor of late AF recurrence after RFA. ROC analysis revealed that a 123I-MIBG washout rate >21% with a sensitivity of 75% and a specificity of 83,3% (AUC=0,844; p<0,001) predicts late AF recurrence after RFA.Conclusion. Parameters of myocardial sympathetic activity, assessed by 123I-MIBG myocardial scintigraphy, are associated with late AF recurrence after RFA in patients with persistent and long-standing persistent AF. There were no reliable data confirming associations between myocardial sympathetic innervation and radiological EAT indicators, as well as the effect of the latter on the risk of AF recurrence after RFA