Coherent single atom shuttle between two Bose-Einstein condensates

We study an atomic quantum dot representing a single hyperfine "impurity" atom which is coherently coupled to two well-separated Bose-Einstein condensates, in the limit when the coupling between the dot and the condensates dominates the inter-condensate tunneling coupling. It is demonstrated that the quantum dot by itself can induce large-amplitude Josephson-like oscillations of the particle imbalance between the condensates, which display a two-frequency behavior. For noninteracting condensates, we provide an approximate solution to the coupled nonlinear equations of motion which allows us to obtain these two frequencies analytically.Comment: 4 pages of RevTex4, 4 figures; Rapid Communication in Physical Review

Energy resolution of terahertz single-photon-sensitive bolometric detectors

We report measurements of the energy resolution of ultra-sensitive superconducting bolometric detectors. The device is a superconducting titanium nanobridge with niobium contacts. A fast microwave pulse is used to simulate a single higher-frequency photon, where the absorbed energy of the pulse is equal to the photon energy. This technique allows precise calibration of the input coupling and avoids problems with unwanted background photons. Present devices have an intrinsic full-width at half-maximum energy resolution of approximately 23 terahertz, near the predicted value due to intrinsic thermal fluctuation noise.Comment: 11 pages (double-spaced), 5 figures; minor revision

Multiple Andreev Reflections in Weak Links of Superfluid 3He-B

We calculate the current-pressure characteristics of a ballistic pinhole aperture between two volumes of B-phase superfluid 3He. The most important mechanism contributing to dissipative currents in weak links of this type is the process of multiple Andreev reflections. At low biases this process is significantly affected by relaxation due to inelastic quasiparticle-quasiparticle collisions. In the numerical calculations, suppression of the superfluid order parameter at surfaces is taken into account self-consistently. When this effect is neglected, the theory may be developed analytically like in the case of s-wave superconductors. A comparison with experimental results is presented.Comment: 12 pages, 9 figures, RevTeX

THE CHARACTERISTIC OF MICROCRYSTALLIZATION OF THE SALIVA AT THE ADULTS HAVING DISEASES OF SIALADENS

Questions of diagnosis and treatment of diseases of the salivary glands extensively researched the leading clinics of maxillofacial surgery and dentistry dental universities and medical academies. Features of a microcrystallization of oral liquid at adults of the different age groups having various chronic diseases of sialadens are studied. In work it is surveyed 246 (115 men and 134 women) aged from 25 till 82 years suffering from a chronic sialadenitis (sialodochitis), sialolithic illness (sialolithiasis), reactive and dystrophic diseases of sialadens (sialoses), radial and medicamental sialoadenopathia, and also good-quality and malignant neoplasms of sialadens. Dependence of crystallographic indicators of the saliva, both from a type of pathology of sialadens, and from age and the level of a comorbidity of adults is established

Anthropometric indices and their relationship with poor prognosis in patients with coronary artery disease and obesity

Aim. To assess the association of anthropometric indices in patients with coronary artery disease (CAD) and obesity and to study their predictive value in the development of adverse cardiovascular events.Material and methods. The study included 229 patients with CAD (median age, 55±7,56 years). Depending on the presence of obesity according to the World Health Organization criteria (1999), patients were divided into 2 groups. The 1st group included 107 obese patients, while the 2nd group — those without obesity (n=122). The groups were comparable in age. We measured waist (WC) and hip circumference (HC), followed by waist-to-hip ratio and body mass index calculation. The lipid profile parameters were determined by the enzymatic colorimetric method. During the study, the following indices were calculated: body mass index, visceral adiposity index, insulin resistance index, body shape index (BSI), fasting triglyceride (TG)/plasma glucose index, waist-to-height ratio, lipid accumulation product, TG-to-high density lipoprotein cholesterol ratio.Results. During the follow-up period, adverse cardiovascular events in the 1st group of patients were found in 37 (34,5%) patients, while in the 2nd group, the composite endpoint was revealed in 12,3% of patients. In order to develop a model for predicting the risk of an unfavorable CAD course in obese patients, we performed a logistic regression analysis, which showed that the following were the most significant predictors of unfavorable cardiovascular outcomes: TG/glucose index and BSI.Conclusion. Thus, of all the considered anthropometric indices, only two were associated with unfavorable CAD course — TG/glucose index and BSI. The data obtained indicate the validity of the search for novel useful obesity indicators with a good predictive value

The use of nitinol rods in stabilization of the lumbar spine for patients under 21 years

The outcomes of surgical treatment of 25 young patients with degenerative diseases of the lumbar spine in two groups were compared in patients with nitinol rods (dynamic stabilization) without spondylodesis and with rigid lumbar fixation of titanium rods. Men - 12, women - 13, the average age is 17.6 years (from 16 to 21 years). These patients are divided into 2 groups depending on the stabilization method. Clinical and radiological results were monitored at least 1 year after the operation. In our study we used nitinol rods of 2 standard sizes - 60 and 80 mm. The size and curvature of the bending of the rods is calculated from the average anatomical parameters characteristic of the lumbar spine and lumbosacral junction. In all groups, there were no statistically significant differences in preoperative values and in the control periods of observation of the VAS (for both the back and the lower limb), Oswestry and SF-36 between patients with nitinol and titanium rods (p> 0.05). In both cases (rigid and dynamic stabilization), statistically significant changes were noted in the postoperative period (p <0.01). In both groups, in comparison with preoperative values, improvement was observed in all control periods, which were highly statistically significant (p <0.01). When studying the mobility in stabilized segment with dynamic nitinol rods, it is determined that the mobility, which persists in 1 segment, averages 4.8°. This index is within the limits of measurement error (up to 5°), however, when measuring mobility in two segments, the mobility is 9.6°. Transpedicular fixation of the lumbosacral spine with the use of nitinol rods is an effective technology that allows to keep movements in the lumbosacral spine in combination with a stable fixation. Further study of this technology should continue, including with reference to deformations of the spine

Chemical-potential standard for atomic Bose-Einstein condensates

When subject to an external time periodic perturbation of frequency $f$, a Josephson-coupled two-state Bose-Einstein condensate responds with a constant chemical potential difference $\Delta\mu=khf$, where $h$ is Planck's constant and $k$ is an integer. We propose an experimental procedure to produce ac-driven atomic Josephson devices that may be used to define a standard of chemical potential. We investigate how to circumvent some of the specific problems derived from the present lack of advanced atom circuit technology. We include the effect of dissipation due to quasiparticles, which is essential to help the system relax towards the exact Shapiro resonance, and set limits to the range of values which the various physical quantities must have in order to achieve a stable and accurate chemical potential difference between the macroscopic condensates.Comment: 13 pages, 4 figure

Ultra-Sensitive Hot-Electron Nanobolometers for Terahertz Astrophysics

The background-limited spectral imaging of the early Universe requires spaceborne terahertz (THz) detectors with the sensitivity 2-3 orders of magnitude better than that of the state-of-the-art bolometers. To realize this sensitivity without sacrificing operating speed, novel detector designs should combine an ultrasmall heat capacity of a sensor with its unique thermal isolation. Quantum effects in thermal transport at nanoscale put strong limitations on the further improvement of traditional membrane-supported bolometers. Here we demonstrate an innovative approach by developing superconducting hot-electron nanobolometers in which the electrons are cooled only due to a weak electron-phonon interaction. At T<0.1K, the electron-phonon thermal conductance in these nanodevices becomes less than one percent of the quantum of thermal conductance. The hot-electron nanobolometers, sufficiently sensitive for registering single THz photons, are very promising for submillimeter astronomy and other applications based on quantum calorimetry and photon counting.Comment: 19 pages, 3 color figure