Dynamic response of 1D bosons in a trap

We calculate the dynamic structure factor S(q,omega) of a one-dimensional (1D) interacting Bose gas confined in a harmonic trap. The effective interaction depends on the strength of the confinement enforcing the 1D motion of atoms; interaction may be further enhanced by superimposing an optical lattice on the trap potential. In the compressible state, we find that the smooth variation of the gas density around the trap center leads to softening of the singular behavior of S(q,omega) at Lieb-1 mode compared to the behavior predicted for homogeneous 1D systems. Nevertheless, the density-averaged response remains a non-analytic function of q and omega at Lieb-1 mode in the limit of weak trap confinement. The exponent of the power-law non-analyticity is modified due to the inhomogeneity in a universal way, and thus, bears unambiguously the information about the (homogeneous) Lieb-Liniger model. A strong optical lattice causes formation of Mott phases. Deep in the Mott regime, we predict a semi-circular peak in S(q,\omega) centered at the on-site repulsion energy, omega=U. Similar peaks of smaller amplitudes exist at multiples of U as well. We explain the suppression of the dynamic response with entering into the Mott regime, observed recently by D. Clement et al., Phys. Rev. Lett. v. 102, p. 155301 (2009), based on an f-sum rule for the Bose-Hubbard model.Comment: 24 pages, 11 figure

SiGe quantum dots for fast hole spin Rabi oscillations

We report on hole g-factor measurements in three terminal SiGe self-assembled quantum dot devices with a top gate electrode positioned very close to the nanostructure. Measurements of both the perpendicular as well as the parallel g-factor reveal significant changes for a small modulation of the top gate voltage. From the observed modulations we estimate that, for realistic experimental conditions, hole spins can be electrically manipulated with Rabi frequencies in the order of 100MHz. This work emphasises the potential of hole-based nano-devices for efficient spin manipulation by means of the g-tensor modulation technique

Erythron and protein system in piglets blood under stress influence

The article presents the results of research on the development of adaptive syndrome in the system of erythron and protein of piglets at the effects of weaning stress. After one (anesthetic stage) and seven days (beginning of G.Selle's resistance stage), after the echoing, the adaptation of the erythron system was shown by a decrease in the number of red blood cells on the contrary of increasing the mean corpuscular volume and hemoglobin indicating the inhibition of erythrocytosis with simultaneous macrocytosis, and a decrease in mean Corpuscular hemoglobin concentration for 14.0–13.0 % that indicated hypochromia. In these stressful periods, the catabolism of protein substrates was discovered, the redistribution of albumins between blood and tissues in the form of a decrease in the total protein content by 6.1–7.1 % due to albumin by 14.8–10.0 %, and the deficit of the humoral link of the immune response due to reduction of γ-globulins by 29.9–18.7 %. In the later stages of the resistance stage (after 20 and 60 days after weaning), there was a stabilization of erythrocytic indices and the development of anisocytosis in the form of an increase in red cell distribution width by 19.0 %, with a simultaneous decrease of 6.1 % of the total protein content, redistribution of its fractions in the side of the growth of γ-globulins by 18.4 %. A practical, prolonged way of preventing disorders in the erythron and protein of extramarital piglets was feeding the additive “Biovir”, which stimulated the intensity of oxidative-reducing processes and the exchange of proteins

Nucleon Resonance Structure from CLAS and CLAS12 Experiments

The recent results on the photo- and electrocouplings extraction from the reaction of one- and two-pion photo- and electroproduction off protons in the resonances region are presented. The production of two charged pions is of particular importance for evaluation of the photocouplings for the Δ(1620)12 −, Δ(1700)32 −

Особливості морфологічного складу крові і показників клінічного стату-су у бугайців на завершальному етапі відгодівлі за корекції раціону комплексом вітамінів групи В (В1, В2, В5, В6, В10, В12)

In realization of the genetic productivity potential of different species of farm animals, an important place is given to full feeding. Insufficient supply of farm animals with individual vitamins has negative impact on the activity of the relevant enzyme systems, hormonal status, metabolism of nutrients, the state of the natural resistance of the various organs and organ systems, the processes of adaptation and productivity level. Numerical searches have shown that farm animals need in different vitamins depends on the type, age, sex, physiological state, the season, the level of productivity and others. According to some reports ruminants have been providing with water-soluble B vitamins  by their rumen microbial synthesis accordingly it was recommended to rations setting for cattle, sheep and goats, along with nutrients and minerals only by carotene and vitamins D and E. Specific features of the effect of different doses of complex B vitamins (thiamine hydrochloride, riboflavin, niacin, pyridoxine hydrochloride, folic acid, ciankobalamin in venous blood) on morphological composition (erythrocytes, leukocytes, platelets, hemoglobin, hematocrit, erythrocyte sedimentation rate) and clinical indicators (heart rate, respiratory rate, type temperature) at the final stage bull fattening. Studies have shown that the addition to the diet of calves for fattening balanced nutrients and minerals and fat-soluble vitamins A, D, E complex of B vitamins (В1, В2, В5, В6, В10, В12) in appropriate doses generally positive effect on erythrocytes, leukocytes, hemoglobin, hematocrit, dose-dependent additionally introduced into the diet of B vitamins (В1, В2, В5, В6, В10, В12). The basis for our dosage of various B vitamins for Bovine experimental groups on fattening is the corresponding percentage of the recommended doses of certain B vitamins for fattening pigs (10 % – D1, 20 % – D2, 40 % – D3, 60 % – D4 group). The biggest change in terms on morphological composition in animals 3rd ((В1 – 0,040; В2 – 0,06; В5 – 1.2; В6 – 0.25; В10 – 0.0030; В12 – 0.0006 mg/kg body weight) and 4th (В1 – 0.070; В2 – 0.10; В5 – 2.0; В6 – 0.40; В10 – 0.0050; В12 – 0.0010 mg/kg body weight) research groups, and smallest – in bull 1st (В1 – 0.015; В2 – 0.03; В5 – 0.5; В6 – 0.10; В10 – 0.0012; В12 – 0.0002 mg/kg body weight) and 2 th (В1 – 0.025;  В2 – 0.04; В5 – 0.8; В6 – 0.15; В10 – 0.0020; В12 – 0.0004 mg/kg body weight) research group, which is associated with dose introduced to the diet of calves during the final fattening phase of B vitamins (В1, В2, В5, В6, В10, В12).Висвітлюються особливості впливу різних доз комплексу вітамінів групи В (В1, В2,  В5, В6, В10, В12) на морфологічний склад крові (кількість еритроцитів, лейкоцитів, тромбоцитів, гематокрит, швидкість осідання еритроцитів (ШОЕ), колірний показник, вміст гемоглобіну) і показники клінічного статусу (частота серцевих скорочень, частота дихання, температура тіла) у бугайців на заключному етапі відгодівлі. Дослідження проведено у зимово-весняний стійловий період на бугайцях української чорно-рябої молочної породи віком 12 місяців. За принципом аналогів було сформовано 5 груп дослідних тварин (контрольну і 4 дослідні) по 6 голів у кожній. Дослід тривав 6 місяців. Раціони для дослідних груп бугайців складені відповідно до рекомендованих норм із врахуванням хімічного складу кормів даної місцевості, віку тварин, живої маси, планованих середньодобових приростів. Для годівлі бугайців використовували силосний тип відгодівлі. В основу нашого дозування різних вітамінів групи В для бугайців дослідних груп на відгодівлі взято відповідний відсоток від рекомендованих доз окремих вітамінів групи В для свиней на відгодівлі (10 % – Д1, 20 % – Д2, 40 % – Д3, 60 % – Д4 група). Проведені дослідження показали, що додавання до раціону бугайців на відгодівлі збалансованого за поживними і мінеральними речовинами та жиророзчинними вітамінами А, D, Е комплексу вітамінів групи В (В1, В2, В5, В6, В10, В12) у відповідних дозах в цілому позитивно впливає на кількісні величини морфологічного складу крові (гемопоез), і несуттєво проявляє дію на показники клінічного статусу (частоту серцевих скорочень, частоту дихання, температуру тіла) бугайців на відгодівлі, що  залежить від дози додатково введених до раціону вітамінів групи В (В1, В2, В5, В6, В10, В12). Найбільші зміни у показниках гемопоезу і клінічного статусу у бугайців на відгодівлі за корекції їх раціону комплексом вітамінів групи В (В1, В2,  В5, В6, В10, В12) встановлено у тварин 3-ї  (В1 – 0,040; В2 – 0,06; В5 – 1,2; В6 – 0,25; В10 – 0,0030; В12 – 0,0006 мг/кг живої маси)  та 4-ї дослідних груп (В1 – 0,070; В2 – 0,10; В5 – 2,0; В6 – 0,40; В10 – 0,0050; В12 – 0,0010 мг/кг живої маси), а найменші – у бугайців 1-ї дослідної групи (В1 – 0,015;  В2 – 0,03; В5 – 0,5; В6 – 0,10;  В10 – 0,0012; В12 – 0,0002 мг/кг живої маси), що пов’язано із кількістю введених до раціону бугайців на заключному етапі відгодівлі вітамінів групи В (В1, В2,  В5, В6, В10, В12)

Spin relaxation at the singlet-triplet crossing in a quantum dot

We study spin relaxation in a two-electron quantum dot in the vicinity of the singlet-triplet crossing. The spin relaxation occurs due to a combined effect of the spin-orbit, Zeeman, and electron-phonon interactions. The singlet-triplet relaxation rates exhibit strong variations as a function of the singlet-triplet splitting. We show that the Coulomb interaction between the electrons has two competing effects on the singlet-triplet spin relaxation. One effect is to enhance the relative strength of spin-orbit coupling in the quantum dot, resulting in larger spin-orbit splittings and thus in a stronger coupling of spin to charge. The other effect is to make the charge density profiles of the singlet and triplet look similar to each other, thus diminishing the ability of charge environments to discriminate between singlet and triplet states. We thus find essentially different channels of singlet-triplet relaxation for the case of strong and weak Coulomb interaction. Finally, for the linear in momentum Dresselhaus and Rashba spin-orbit interactions, we calculate the singlet-triplet relaxation rates to leading order in the spin-orbit interaction, and find that they are proportional to the second power of the Zeeman energy, in agreement with recent experiments on triplet-to-singlet relaxation in quantum dots.Comment: 29 pages, 14 figures, 1 tabl

Theoretical simulation of parameters of cleaning sugar beet heads from remnants of leaves by flexible blade

In our previous works we obtained analytical dependencies characterising the impact interaction that arises when the heads of the root crops are cleaned from the remnants of tops (leaves) by means of a flexible cleaning blade. In order to find a more perfect and complete result, which could be used by the designers of sugar beet harvesting machines, the research in this technological process needs to be continued in the direction of numerical simulation of the dependencies on the PC. In accordance with the compiled programme of numerical calculations in the Mathcad system, numerical calculations were executed of the kinematic and design parameters of a flexible cleaning blade depending on the design parameters of the cleaning blade, the physical and mechanical properties of the sugar beet tops (leaves) and conditions of cleaning without extracting the roots themselves from the soil. On the basis of the results of calculations graphical dependencies were built of the angular velocity ω of the rotational movement of the flexible cleaning blade upon the indicated parameters of the cleaner, allowing estimation of their optimal value

Millisecond-range electron spin memory in singly-charged InP quantum dots

We report millisecond-range spin memory of resident electrons in an ensemble of InP quantum dots (QDs) under a small magnetic field of 0.1 T applied along the optical excitation axis at temperatures up to about 5 K. A pump-probe photoluminescence (PL) technique is used for optical orientation of electron spins by the pump pulses and for study of spin relaxation over the long time scale by measuring the degree of circular polarization of the probe PL as a function of pump-probe delay. Dependence of spin decay rate on magnetic field and temperature suggests two-phonon processes as the dominant spin relaxation mechanism in this QDs at low temperatures.Comment: 3 pages, 4 figures, submitted to Appl. Phys. Let

On the nature of tunable hole g-factors in quantum dots

Electrically tunable g-factors in quantum dots are highly desirable for applications in quantum computing and spintronics. We report giant modulation of the hole g-factor in a SiGe nanocrystal when an electric field is applied to the nanocrystal along its growth direction. We derive a contribution to the g-factor that stems from an orbital effect of the magnetic field, which lifts the Kramers degeneracy in the nanocrystal by altering the mixing between the heavy and the light holes. We show that the relative displacement between the heavy- and light-hole wave functions, occurring upon application of the electric field, has an effect on the mixing strength and leads to a strong non-monotonic modulation of the g-factor. Despite intensive studies of the g-factor since the late 50's, this mechanism of g-factor control has been largely overlooked in the literature.Comment: 9 pages, 6 figure