Statistical mechanics of Floquet systems with regular and chaotic states

We investigate the asymptotic state of time-periodic quantum systems with regular and chaotic Floquet states weakly coupled to a heat bath. The asymptotic occupation probabilities of these two types of states follow fundamentally different distributions. Among regular states the probability decreases from the state in the center of a regular island to the outermost state by orders of magnitude, while chaotic states have almost equal probabilities. We derive an analytical expression for the occupations of regular states of kicked systems, which depends on the winding numbers of the regular tori and the parameters temperature and driving frequency. For a constant winding number within a regular island it simplifies to Boltzmann-like weights \exp(-\betaeff \Ereg_m), similar to time-independent systems. For this we introduce the regular energies \Ereg_m of the quantizing tori and an effective winding-number-dependent temperature 1/\betaeff, different from the actual bath temperature. Furthermore, the occupations of other typical Floquet states in a mixed phase space are studied, i.e. regular states on nonlinear resonances, beach states, and hierarchical states, giving rise to distinct features in the occupation distribution. Avoided crossings involving a regular state lead to drastic consequences for the entire set of occupations. We introduce a simplified rate model whose analytical solutions describe the occupations quite accurately.Comment: 18 pages, 11 figure

Transverse Magnetic Anisotropy in Mn12-acetate: Direct Determination by Inelastic Neutron Scattering

A high resolution inelastic neutron scattering (INS) study of fully deuterated Mn$_{12}$-acetate provides the most accurate spin Hamiltonian parameters for this prototype single molecule magnet so far. The Mn$_{12}$-clusters deviate from axial symmetry, a non-zero rhombic term in the model Hamiltonian leading to excellent agreement with observed positions and intensities of the INS peaks. The following parameter set provides the best agreement with the experimental data: $D=-0.0570(1)$ meV, $B_{4}^0=-2.78(7)\cdot 10^{-6}$ meV, $B_{4}^4=-3.2(6)\cdot 10^{-6}$ meV and $\mid$\textit{E}$\mid =6.8(15)\cdot 10^{-4}$ meV. Crystal dislocations are not the likely cause of the symmetry lowering. Rather, this study lends strong support to a recently proposed model, which is based on the presence of several molecular isomers with distinct spin Hamiltonian parameters.Comment: 4 pages, 4 figure

The ``Out-Longitudinal'' Cross Term and Other Model Independent Features of the Two-Particle HBT Correlation Function

Using two specific models and a model independent formalism, we show that an ``out-longitudinal'' cross term should be included in any gaussian fits to correlation data. In addition, we show that correlation radii (including the cross term) measure lengths of homogeneity within the source, not necessarily geometric sizes.Comment: 4 pages, uuencoded compressed postscrip

EVALUATION OF SPEED-TESTS FOR PLAYERS OF SPORT GAMES

PROBLEM. The characteristics demands of the load of the common sport games are different, but many similarities are obvious. 'They all require a high ability of anticipation. reaction- and action speed. Many actions like dribbling, feint. tracing and attacking adversary are carried out with highest intensity (speed) in combination with rapid changes in direction of motion In split seconds decisions between alternative movements must be reached and go into action. The available speed tests were not able to satis6 these requirements (e.g. 1, 2). The aim of this study was to evaluate tests for speed-diagnostics. which consider the specific demands of the sport games soccer, handball, tennis. MEI'HODS The length of the run and the kind of changes of direction depends on the conditions of the sport game For the time recording we used a measuring system of 4 double lightbars Each run starts from a defined position on a contact platform. The starts were free selected and/or given by an optical signal. The following abilities here recorded differently in separate tests: 4 the ability to start and accelerate straight on. I3 the ability to start. decelerate. accelerate in connection with changes in direction of motion the ability to react in connection \kith selection and following game specific movement. calculated by test-retest correlation coefficient To check the selectivity of the tests analysis of variance were used to calculate significant differences. KESliL.T.5 - the reliability of the evaluated tests are in the range of rtt = 72 - .98. and therefore altogether acceptable - the selectivity of the tests is also acceptable in general ( exception. test .4 for Tennis plavers). - the great intraindividuell differences between runners with turns to the left and right. as well as between the players within a team illustrate the necessarity from precise diagnostics A few number of training sessions will eliminate individual deficit

Switching mechanism in periodically driven quantum systems with dissipation

We introduce a switching mechanism in the asymptotic occupations of quantum states induced by the combined effects of a periodic driving and a weak coupling to a heat bath. It exploits one of the ubiquitous avoided crossings in driven systems and works even if both involved Floquet states have small occupations. It is independent of the initial state and the duration of the driving. As a specific example of this general switching mechanism we show how an asymmetric double well potential can be switched between the lower and the upper well by a periodic driving that is much weaker than the asymmetry.Comment: 5 pages, 5 figure

Jet quenching via jet collimation

The strong modifications of dijet properties in heavy ion collisions measured by ATLAS and CMS provide important constraints on the dynamical mechanisms underlying jet quenching. In this work, we show that the transport of soft gluons away from the jet cone - jet collimation - can account for the observed dijet asymmetry with values of $\hat{q}\, L$ that lie in the expected order of magnitude. Further, we show that the energy loss attained through this mechanism results in a very mild distortion of the azimuthal angle dijet distribution.Comment: 4 pages, 2 figures; Proceedings of the "Quark Matter 2011" conferenc

Nuclear collisions at the Future Circular Collider

The Future Circular Collider is a new proposed collider at CERN with centre-of-mass energies around 100 TeV in the pp mode. Ongoing studies aim at assessing its physics potential and technical feasibility. Here we focus on updates in physics opportunities accessible in pA and AA collisions not covered in previous Quark Matter contributions, including Quark-Gluon Plasma and gluon saturation studies, novel hard probes of QCD matter, and photon-induced collisions.Comment: 4 pages, 5 figures, proceedings of Quark Matter 201

Electron Transport Through Molecules: Self-consistent and Non-self-consistent Approaches

A self-consistent method for calculating electron transport through a molecular device is proposed. It is based on density functional theory electronic structure calculations under periodic boundary conditions and implemented in the framework of the nonequilibrium Green function approach. To avoid the substantial computational cost in finding the I-V characteristic of large systems, we also develop an approximate but much more efficient non-self-consistent method. Here the change in effective potential in the device region caused by a bias is approximated by the main features of the voltage drop. As applications, the I-V curves of a carbon chain and an aluminum chain sandwiched between two aluminum electrodes are calculated -- two systems in which the voltage drops very differently. By comparing to the self-consistent results, we show that this non-self-consistent approach works well and can give quantitatively good results.Comment: 11 pages, 10 figure

Feeding Programs for Newly Arrived or Recently Weaned Calves

Fall is a stressful time for calves. They are generally weaned at this time. Following weaning, they are often transported or moved to a sale barn or unfamiliar facility. Upon arrival, they may be mixed with other cattle, subjected to processing and forced to eat unfamiliar feeds. In addition, all of these stresses may be compounded by foul weather. To combat the negative impacts of stress cattlemen should strive to get new calves on feed as rapidly as possible. Proper nutrition and a consistent health program are essential when starting calves on feed. Proper nutrition is important from two standpoints. First, the success of any health program is highly dependant on the nutritionals status of the calf. In order for the immune system of the calf to form antibodies in response to vaccination programs, sufficient protein, energy vitamins and minerals must be available. The second reason is more obvious. The calf simply needs to consume feed in order to grow and thrive. Ownership and facility costs are generally high. Feeder cattle need to gain weight in order to make money for cattlemen. Newly arrived or recently weaned calves do not readily eat upon arrival in a feedlot. Texas data (Hutcheson, 1980) suggests that a surprisingly high percentage of cattle do not eat during the first few days in the feedlot. Table 1 shows that on day one in the feedlot, only 21.7% of the cattle eat. On day three, over 40% of the cattle will not eat. On seven, 30% of the cattle will not eat. And on day 10, an average of 15% of the cattle will not eat. These data suggest that getting cattle started on feed is a major problem. Three problems need to be addressed in order to get cattle started on feed. First, recently weaned or newly arrived cattle will generally not recognize the feed bunk and may not recognize water troughs. Second, new cattle may not recognize the feed that the producer wishes to feed him. Finally, feed intake by new cattle will likely be low due to stress. The remaining section of this paper focus on managing around these problems. Additional sections include discussions of feed additives, commercial receiving, or weaning rations and health programs

Ignition of typical gel-fuel at local heating

In this paper, we determined the ignition delay for a typical gel fuel by metal particles of various form. Also, determined the ignition delay times by varying the initial particle temperature