Superfluid-insulator transition of the Josephson junction array model with commensurate frustration

We have studied the rationally frustrated Josephson-junction array model in the square lattice through Monte Carlo simulations of $(2+1)$D XY-model. For frustration $f=1/4$, the model at zero temperature shows a continuous superfluid-insulator transition. From the measurement of the correlation function and the superfluid stiffness, we obtain the dynamical critical exponent $z=1.0$ and the correlation length critical exponent $\nu=0.4 \pm 0.05$. While the dynamical critical exponent is the same as that for cases $f=0$, 1/2, and 1/3, the correlation length critical exponent is surprisingly quite different. When $f=1/5$, we have the nature of a first-order transition.Comment: RevTex 4, to appear in PR

What situations trigger intense emotions in automobiles?

Conference ProceedingsDriving involves a variety of events and activities that stimulate emotional experiences. The aim of this investigation was to examine automobile experiences and to identify affective themes. 245 UK-based participants were recruited using a purposive sampling strategy. One study consisted of an online questionnaire which inquired about the automotive experiences which proved most emotionally intense. The second consisted of a simulator based immersive driving experience, followed afterwards by a questionnaire which inquired about the automotive experiences which proved most emotionally intense. Questionnaire responses were clustered into themes using a content analysis method. The study identified 13 major themes and 44 sub-themes. The findings provide guidance regarding the triggers of emotional responses which designers can use to better understand and to improve automotive experiences.Jaguar Land Rover as part of project Automotive Habitat Laboratory (AutoHablab)

BRST Quantization of the Proca Model based on the BFT and the BFV Formalism

The BRST quantization of the Abelian Proca model is performed using the Batalin-Fradkin-Tyutin and the Batalin-Fradkin-Vilkovisky formalism. First, the BFT Hamiltonian method is applied in order to systematically convert a second class constraint system of the model into an effectively first class one by introducing new fields. In finding the involutive Hamiltonian we adopt a new approach which is more simpler than the usual one. We also show that in our model the Dirac brackets of the phase space variables in the original second class constraint system are exactly the same as the Poisson brackets of the corresponding modified fields in the extended phase space due to the linear character of the constraints comparing the Dirac or Faddeev-Jackiw formalisms. Then, according to the BFV formalism we obtain that the desired resulting Lagrangian preserving BRST symmetry in the standard local gauge fixing procedure naturally includes the St\"uckelberg scalar related to the explicit gauge symmetry breaking effect due to the presence of the mass term. We also analyze the nonstandard nonlocal gauge fixing procedure.Comment: 29 pages, plain Latex, To be published in Int. J. Mod. Phys.

Flux-flow resistivity of three high-temperature superconductors

Results of experiments on flux-flow resistivity (the relationship of voltage to current) of three high-temperature superconductors are described. The superconductors are a melt-cast BSCCO 2212 rod, a single filament BSCCO powder-in-tube (PIT) tape, and a multifilament PIT tape. The flux-flow resistivity of these superconductors was measured at three temperatures: 77 K (saturated liquid nitrogen), 87 K (saturated liquid argon), and 67 K (subcooled liquid nitrogen). Implications of the present results for practical applications are discussed

Nova-Like Cataclysmic Variable TT Ari: QPO Behaviour Coming Back From Positive Superhumps

We study the variability of the nova-like cataclysmic variable TT Ari, on time-scales of between minutes and months. The observations in the filter R were obtained at the 40-cm telescope of the Chungbuk National University (Korea). TT Ari was in the "negative superhump" state after its return from the "positive superhump" state, which lasted 8 years. The ephemeris for 12 best pronounced minima is $T_{min}=BJD 2453747.0700(47)+0.132322(53)E.$ where numbers in digits are errors in units of the last digit. The phases of minima may reach 0.2, indicating non-eclipse nature of these minima. The quasi-periodic oscillations (QPO) are present with a mean "period" of 21.6 min and mean semi-amplitude of 36 mmag. This value is consistent with the range 15-25 minutes reported for previous "negative superhump" states and does not support the hypothesis of secular decrease of the QPO period. Either the period, or the semi-amplitude show significant night-to-night variations. According to the position at the two-parameter diagrams, the interval of observations was splitted into 5 parts, showing different characteristics which are discussed in this paper. The system is an excellent laboratory to study processes resulting in variations at time-scales from seconds to decades and needs further monitoring at various states of activity.Comment: 14pages,10figures, accepted in Astronomy and Astrophysic