Using adiabatic coupling techniques in atom-chip waveguide structures

Adiabatic techniques are well known tools in multi-level electron systems to transfer population between different states with high fidelity. Recently it has been realised that these ideas can also be used in ultra-cold atom systems to achieve coherent manipulation of the atomic centre-of-mass states. Here we present an investigation into a realistic setup using three atomic waveguides created on top of an atom chip and show that such systems hold large potential for the observation of adiabatic phenomena in experiments.Comment: 10 pages, 6 figures, accepted for publication in Physica Scripta for the CEWQO2009 proceeding

Analysis of the entanglement between two individual atoms using global Raman rotations

Making use of the Rydberg blockade, we generate entanglement between two atoms individually trapped in two optical tweezers. In this paper we detail the analysis of the data and show that we can determine the amount of entanglement between the atoms in the presence of atom losses during the entangling sequence. Our model takes into account states outside the qubit basis and allows us to perform a partial reconstruction of the density matrix describing the two atom state. With this method we extract the amount of entanglement between pairs of atoms still trapped after the entangling sequence and measure the fidelity with respect to the expected Bell state. We find a fidelity $F_{\rm pairs} =0.74(7)$ for the 62% of atom pairs remaining in the traps at the end of the entangling sequence

Sublattice addressing and spin-dependent motion of atoms in a double-well lattice

We load atoms into every site of an optical lattice and selectively spin flip atoms in a sublattice consisting of every other site. These selected atoms are separated from their unselected neighbors by less than an optical wavelength. We also show spin-dependent transport, where atomic wave packets are coherently separated into adjacent sites according to their internal state. These tools should be useful for quantum information processing and quantum simulation of lattice models with neutral atoms

Vitis vinifera L. germplasm diversity: a genetic and ampelometric study in ancient vineyards in the South of Basilicata region (Italy)

The evaluation of the existing grapevines biodiversity in several areas still unexplored in Basilicata region has been carried out. A four years survey in ancient vineyards of Potenza was performed to investigate grapevine biodiversity. 85 collected accessions were subjected to genetic characterization through nine microsatellite markers. A total of 42 genotypes were obtained. The comparison with national and international databases allowed the identification of 26 accessions corresponded to new autochthonous genotypes and minor/local cultivars, in addition 16 international and national cultivars commonly cultivated in several Italian regions were found (data not shown in this work). Results indicated that minor/local cultivars were mainly cultivated in the near regions. The genetic profile of 9 new autochthonous grapevines was described here for the first time. Comparison of the genotypes, allelic frequencies, allelic sizes and ampelometric traits on mature leaves are highlighted. Conservation of new autochthonous and minor/local cultivars in germoplasm collections has been carried out including them in the germoplasm collection of CREA-VE in Arezzo in order to save grapevine biodiversity and allows further agronomical and enological evaluation

SPATIO-TEMPORAL PARAMETERS AND INSTANTANEOUS VELOCITY OF SPRINT RUNNING USING A WEARABLE INERTIAL MEASUREMENT UNIT

INTRODUCTION: Wearable inertial measurement units (IMU) provide movement-related data without any space limitation or cumbersome setup. They can be proficiently used to perform an in-field biomechanical analysis of sprint running providing information useful for performance optimisation and injury prevention. Mechanical key quantities characterizing sprint running performance are instantaneous velocity and displacement of the athlete (Cavagna et al., 1971). However, the process of determining velocity and position by numerical integration of acceleration is jeopardized by the noise characterizing the signal of micro-machined accelerometers (Thong et al., 2002). The aim of this study was to compensate these errors by reducing the integration interval, taking advantage of a priori known laws of motion, and by cyclically determining the initial conditions of the integration process, in order to yield reliable spatio-temporal parameters during sprint running. METHODS: A male subject (26 yrs, 73 kg, 1.73 m) performed 7 in-lab sprints, starting from a standing position. Due to limited lab volume (12*9*4 m) only the first 3 steps were considered. 3D linear acceleration and orientation of a wearable IMU positioned on the upper back trunk (MTx, Xsens; m=30g) were collected and the following parameters were estimated over each cycle: 1) stance time (ST); 2) centre of mass progression displacement (d); 3) variation of vertical and progression velocity (Δvv, Δvp). Reference data were obtained as follows: ST from a contact-sensitive mat (stance 1) and two force platforms (Bertec) (stance 2-3); Δv and d from stereophotogrammetry (Vicon MX, Plug-in-Gait protocol). The average of the absolute percentage difference (eabs%=|(reference-inertial)*100/reference|), referred to as error (e%), was calculated for each parameter. RESULTS: Reference and sensor estimates and percentage error are reported in Table 1. DISCUSSION AND CONCLUSION: The obtained Δv percentage errors are consistent with respect to the literature (Vetter et al., 2008). Even though these errors still increase at each stance phase, the methodology is sensitive to the variations of velocity determined by the reference measurement system. As regards ST and d, no similar previous study has been reported. However since the methodology relies on the identification of foot contact timings for reducing the integration interval, small errors in the determination of these parameters, are encouraging. Future developments concern in-field sprint running experimental sessions

Bose-Einstein condensation in dark power-law laser traps

We investigate theoretically an original route to achieve Bose-Einstein condensation using dark power-law laser traps. We propose to create such traps with two crossing blue-detuned Laguerre-Gaussian optical beams. Controlling their azimuthal order $\ell$ allows for the exploration of a multitude of power-law trapping situations in one, two and three dimensions, ranging from the usual harmonic trap to an almost square-well potential, in which a quasi-homogeneous Bose gas can be formed. The usual cigar-shaped and disk-shaped Bose-Einstein condensates obtained in a 1D or 2D harmonic trap take the generic form of a "finger" or of a "hockey puck" in such Laguerre-Gaussian traps. In addition, for a fixed atom number, higher transition temperatures are obtained in such configurations when compared with a harmonic trap of same volume. This effect, which results in a substantial acceleration of the condensation dynamics, requires a better but still reasonable focusing of the Laguerre-Gaussian beams

THE TRUNK ORIENTATION DURING SPRINT START ESTIMATED USING A SINGLE INERTIAL SENSOR

Sprint start and block acceleration are two very important phases which could determine the result of a sprint. Tellez & Doolittle (1984) showed that these two phases account for 64% of the total result for a 100m sprint. Sprinters have to move from a crouch to a standing position, trying to reach their maximal velocity as fast as possible. Many authors have delved into the biomechanical factors concerning both phases (Fortier et al., 2005; Harland & Steele, 1997; Schot & Knutzen, 1992). Trunk orientation is considered by coaches one of the key elements in moving from the crouch to the upright position, however only a few studies focused specifically on this parameter (Čoh et al., 1998; Čoh et al., 2006; Natta et al., 2006). Moreover, the experimental setups used in the latter studies are quite cumbersome and limited in terms of acquisition volume (motion capture systems, high-speed cameras or optical contact time meters), therefore, they are hardly usable during everyday training sessions. Wearable inertial measurement units (IMU), that embed 3D linear acceleration and angular rate sensors (accelerometers and gyroscopes), can be effectively used to perform in-field biomechanical analysis of sprint running, providing information useful for performance optimisation and injury prevention. In particular, IMUs provide an estimate of body segment rotations relative to an inertia system of reference with one axis oriented as the gravitational field. The aim of this pilot study is to validate the use of a single IMU to estimate the trunk orientation angle in the progression plane during a sprint start from the blocks

ROUNDHOUSE KICK WITH AND WITHOUT IMPACT IN KARATEKA OF DIFFERENT TECHNICAL LEVEL

The purpose of this study was to compare two different Karate roundhouse kicks performed by athletes of different technical level. The combination of high movement velocities and a high technical difficulty, qualify these actions as a good model to quantify the ability of a Karateka to execute complex movements. The first kick, directed to the face, entails a strong braking action to avoid the impact (NI), the other, directed to the chest, is concluded by an impact (IM). Technical aspects and the role of muscular co-activation as joint protector were investigated in six top level Karateka (KA) and six practicing karate amateurs (CO), by estimating joint kinematics and neuromuscular activity patterns. KA presented a faster execution for both tasks, prevalently due to a faster knee extension, supported by a low co-activation of the antagonist Biceps Femoris. This behaviour confirms that elite KA tend to lower the co-activation of antagonist muscles during fast movements, partially in contrast with the antagonists possible role in maintaining knee stability. The NI task, requiring higher technical competence and entailing a high target, is performed by KA athletes using a peculiar technique, based on a wide hip flexion-extension range, with a peak hip ab-adduction occurring earlier than in CO. A lower co-activation presented by CO during knee flexion is presumably due to their difficulty in mastering this complex kick

Photoredox Allylation Reactions Mediated by Bismuth in Aqueous Conditions

Organometallic allylic reagents are widely used in the construction of C−C bonds by Barbier-type reactions. In this communication, we have described a photoredox Barbier allylation of aldehydes mediated by bismuth, in absence of other metals as co-reductants. Mild reaction conditions, tolerance of oxygen, and use of aqueous solvent make this photoredox methodology attractive for green and sustainable synthesis of homoallylic alcohols