Geometric dependence of Nb-Bi2{_2}Te3{_3}-Nb topological Josephson junction transport parameters

Superconductor-topological insulator-superconductor Josephson junctions have been fabricated in order to study the width dependence of the critical current, normal state resistance and flux periodicity of the critical current modulation in an external field. Previous literature reports suggest anomalous scaling in topological junctions due to the presence of Majorana bound states. However, for most realised devices, one would expect that trivial $2\pi$-periodic Andreev levels dominate transport. We also observe anomalous scaling behaviour of junction parameters, but the scaling can be well explained by mere geometric effects, such as the parallel bulk conductivity shunt and flux focusing

INTEGRATING SPORT BIOMECHANICS AND EXERCISE PHYSIOLOGY FOR TRAINING COLLEGIATE ATHLETES DURING A COMPETITION SEASON

Sport specificity training involves the design and implementation of strength training and conditioning programs tailored to a specific sport with the goal of optimizing performance. When training collegiate athletes during a competition season there is an even greater emphasis placed on optimization. This is because the NCAA places time restrictions on collegiate athletes that effectively limit the volume of training that any one athlete can participate in per week. As a result, coaching staffs need to maximize time devoted to skills based training while still ensuring sufficient time is allocated for developing an athlete to peak physical conditioning and rest (Marques, et al., 2006). The goal of this paper is to present a framework for integrating sport biomechanics and exercise physiology within the design of sport specific training programs. Research from both fields has direct applicability to sport specificity training and integration is often an implicit dimension to such research. Yet, comparably few studies have been explicit about how to best integrate biomechanics and exercise physiology within the context of sport specificity training. Although this paper specifically uses Women’s Collegiate Volleyball as a case study, the intent is to initiate discussion regarding the need to explicitly integrate sport biomechanics and exercise physiology when developing strength training and conditioning programs for collegiate athletes

Experimental realization of SQUIDs with topological insulator junctions

We demonstrate topological insulator (Bi$_2$Te$_3$) dc SQUIDs, based on superconducting Nb leads coupled to nano-fabricated Nb-Bi$_2$Te$_3$-Nb Josephson junctions. The high reproducibility and controllability of the fabrication process allows the creation of dc SQUIDs with parameters that are in agreement with design values. Clear critical current modulation of both the junctions and the SQUID with applied magnetic fields have been observed. We show that the SQUIDs have a periodicity in the voltage-flux characteristic of $\Phi_0$, of relevance to the ongoing pursuit of realizing interferometers for the detection of Majorana fermions in superconductor- topological insulator structures

All-optical octave-broad ultrafast switching of Si woodpile photonic band gap crystals

We present ultrafast all-optical switching measurements of Si woodpile photonic band gap crystals. The crystals are spatially homogeneously excited and probed by measuring reflectivity over an octave in frequency (including the telecommunication range) as a function of time. After 300 fs, the complete stop band has shifted to higher frequencies as a result of optically excited free carriers. The switched state relaxes quickly with a time constant of 18 ps. We present a quantitative analysis of switched spectra with theory for finite photonic crystals. The induced changes in refractive index are well described by a Drude model with a carrier relaxation time of 10 fs. We briefly discuss possible applications of high-repetition-rate switching of photonic crystal cavities

The Individual Day-to-Day Process of Social Anxiety in Vulnerable College Students

Transitions requiring the creation of new social networks may be challenging for individuals vulnerable to social anxiety, which may hinder successful adjustment. Using person-specific methodology, this study examined social anxiety in vulnerable university freshman away from home during their first semester of college to understand how day-to-day processes of social anxiety influenced future social anxiety and social withdrawal. Participants completed daily measures of four components of social anxiety which were examined as a process during a single day, and as a process affecting social anxiety and social withdrawal the next day. For most individuals, same day fear of negative evaluation was associated with maladaptive cognitive processes (anticipatory processing and post-event rumination) and influenced social withdrawal behaviors. Across time relations were less robust and varied between participants suggesting the importance of situational factors and individual differences. These findings may have implications for the effectiveness of various intervention strategies

On compact models for high-voltage MOS devices

Fast evaluation of integrated circuits(ICs) requires the validity of so-called compact models, i.e. simple-to-evaluate relations between the voltages and the currents in the IC-components. In this paper the compact model for a particular IC part, the LDMOS device, is studied

Accurate evaluation of the interstitial KKR-Green function

It is shown that the Brillouin zone integral for the interstitial KKR-Green function can be evaluated accurately by taking proper care of the free-electron singularities in the integrand. The proposed method combines two recently developed methods, a supermatrix method and a subtraction method. This combination appears to provide a major improvement compared with an earlier proposal based on the subtraction method only. By this the barrier preventing the study of important interstitial-like defects, such as an electromigrating atom halfway along its jump path, can be considered as being razed.Comment: 23 pages, RevTe

Josephson supercurrent in a topological insulator without a bulk shunt

A Josephson supercurrent has been induced into the three-dimensional topological insulator Bi1.5Sb0.5Te1.7Se1.3. We show that the transport in Bi1.5Sb0.5Te1.7Se1.3 exfoliated flakes is dominated by surface states and that the bulk conductivity can be neglected at the temperatures where we study the proximity induced superconductivity. We prepared Josephson junctions with widths in the order of 40 nm and lengths in the order of 50 to 80 nm on several Bi1.5Sb0.5Te1.7Se1.3 flakes and measured down to 30 mK. The Fraunhofer patterns unequivocally reveal that the supercurrent is a Josephson supercurrent. The measured critical currents are reproducibly observed on different devices and upon multiple cooldowns, and the critical current dependence on temperature as well as magnetic field can be well explained by diffusive transport models and geometric effects