Coupled Hartree-Fock-Bogoliubov kinetic equations for a trapped Bose gas

Using the Kadanoff-Baym non-equilibrium Green's function formalism, we derive the self-consistent Hartree-Fock-Bogoliubov (HFB) collisionless kinetic equations and the associated equation of motion for the condensate wavefunction for a trapped Bose-condensed gas. Our work generalizes earlier work by Kane and Kadanoff (KK) for a uniform Bose gas. We include the off-diagonal (anomalous) pair correlations, and thus we have to introduce an off-diagonal distribution function in addition to the normal (diagonal) distribution function. This results in two coupled kinetic equations. If the off-diagonal distribution function can be neglected as a higher-order contribution, we obtain the semi-classical kinetic equation recently used by Zaremba, Griffin and Nikuni (based on the simpler Popov approximation). We discuss the static local equilibrium solution of our coupled HFB kinetic equations within the semi-classical approximation. We also verify that a solution is the rigid in-phase oscillation of the equilibrium condensate and non-condensate density profiles, oscillating with the trap frequency.Comment: 25 page

Claimed Co-ethnics and Kin-State Citizenship in Southeastern Europe

The paper introduces the often neglected concept of 'claimed co-ethnics' in the analysis of citizenship policies. It argues that this is an interstitial category that further complicates the triadic nexus between national minorities, nationalising states and kin-states. The 'claimed co-ethnics' are defined as people who are recognised by the citizenship (or ethnizenship) conferring state as belonging to its main ethnic group, although they themselves do not embrace that definition. In addition to bringing the issue of claimed co-ethnics into focus, the paper elucidates how citizenship policies can affect groups that challenge the exact fit between ethnicity and nation, showing how national governments through particular citizenship policies and categorisation practices engage in the construction of these groups. The paper shows that the triadic nexus framework, which has had a strong influence on citizenship and minorities scholarship, needs to be revised to include unidirectional relations between the elements of the triadic nexus. The paper is based on the comparison between the cases of ethnic Vlachs (in the context of Albania and Greece) and Bunjevci (in the context of Serbia and Croatia).European Commission - Seventh Framework Programme (FP7

Bose condensates in a harmonic trap near the critical temperature

The mean-field properties of finite-temperature Bose-Einstein gases confined in spherically symmetric harmonic traps are surveyed numerically. The solutions of the Gross-Pitaevskii (GP) and Hartree-Fock-Bogoliubov (HFB) equations for the condensate and low-lying quasiparticle excitations are calculated self-consistently using the discrete variable representation, while the most high-lying states are obtained with a local density approximation. Consistency of the theory for temperatures through the Bose condensation point requires that the thermodynamic chemical potential differ from the eigenvalue of the GP equation; the appropriate modifications lead to results that are continuous as a function of the particle interactions. The HFB equations are made gapless either by invoking the Popov approximation or by renormalizing the particle interactions. The latter approach effectively reduces the strength of the effective scattering length, increases the number of condensate atoms at each temperature, and raises the value of the transition temperature relative to the Popov approximation. The renormalization effect increases approximately with the log of the atom number, and is most pronounced at temperatures near the transition. Comparisons with the results of quantum Monte Carlo calculations and various local density approximations are presented, and experimental consequences are discussed.Comment: 15 pages, 11 embedded figures, revte

Collisionless dynamics of dilute Bose gases: Role of quantum and thermal fluctuations

We study the low-energy collective oscillations of a dilute Bose gas at finite temperature in the collisionless regime. By using a time-dependent mean-field scheme we derive for the dynamics of the condensate and noncondensate components a set of coupled equations, which we solve perturbatively to second order in the interaction coupling constant. This approach is equivalent to the finite-temperature extension of the Beliaev approximation and includes corrections to the Gross-Pitaevskii theory due both to quantum and thermal fluctuations. For a homogeneous system we explicitly calculate the temperature dependence of the velocity of propagation and damping rate of zero sound. In the case of harmonically trapped systems in the thermodynamic limit, we calculate, as a function of temperature, the frequency shift of the low-energy compressional and surface modes.Comment: 26 pages, RevTex, 8 ps figure

Potential antimicrobial effects of pharmacognostic drugs

Pharmacognostic aspect, in treating of natural medicinal materials and medicinal of natural origin, is presented by very complex group of analytical and applicative methods. They are applied by means of identification, purities and quality of natural medicinal materials of vegetal, animal or mineral origin, more precisely of pharmacognostic drugs. A great number of drugs and their isolated products show the antimicrobial activities. The chemical substances, which are present in drugs, are currier of antimicrobial activities manifested by action on different bacteria, fungus, parasites and even viruses. The whole series of methods for analyzing of antimicrobial effects of drugs and the medicines in general are treated by scientific discipline microbiology. In order to complete the pharmacognostic analyses of drugs and there medicinal products, the microbiological analyses take a very important role. The antimicrobial and antifungal effects of series of plant materials, of pharmacognosticdrugs against the large number of bacteria and fungus Candida have been carried out. The drugs we analyzed were treated from their chemical point of view and that is the presence of: coumarins, mucus and anthraquinones. The contents of these substances in plant material were analyzed by method of thin layer chromatography that was published preliminary. The antimicrobial effects of analyzed drugs were determinate by using dilution method in antimicrobial analyses which have been carried out with decocts of drugs

Differences between morphological characteristics and motoric capabilities of physically active and inactive female students

Background: This research was done as continuation of research made previously on male population. The goal of this research is to determine „differences between morphological characteristics and motoric capabilities of physically active and inactive female students “. Methods: Sample of physically inactive female students was made of 54 examinees and sample for active students was made of 52 girls. Average age was 12. All girls were primary school students. Physically inactive students regularly attended PE lessons and active students were involved in training process of basketball, volleyball, football and handball teams. Additional practice was done two times a week for 90 minutes. Morphological space is set by 15 variables and motoric space is set with 24 variables. Results: Statistical difference was determined by T-test on level (p<0.05). Significance given by T-test was checked by calculating Eta coefficient. Such data has differences in Chest Width (.00/.00 and η2=0,33), Weight (.00/.00 and η2=0,34), Stomach Skin Curves (.00/.00 and η2=0,37) and Back Skin Curves (.05/.05 and η2=0,16). Motoric space has differences in: Slalom with Three Medicine Balls (.00/.00 and η2=0.01), Throwing medicine ball from the chest (.00/.00 and η2=0,10), Long Jump (.00/.00 and η2=0,17), Push-ups (.02/.02 and η2=0.05), Sit-and-Reach (.04/.04 and η2=0.00) and 20m low start run (.00/.00 and. η2=0,14). Conclusions: After analysis it can be stated the aim of the research was completed and differences of anthropological status of physically active and inactive female students were determined. Students of age 12 can be recommended additional training activity to positively transform anthropological spaces with no transformation. Research with same or similar variables should be done on different age categories when compared to this one or to analyze quality of influence that specific sports have on transformation in this age category