1,525 research outputs found

    Neutrino Oscillations with the MINOS, MINOS+, T2K, and NOvA Experiments

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    This paper discusses recent results and near-term prospects of the long-baseline neutrino experiments MINOS, MINOS+, T2K and NOvA. The non-zero value of the third neutrino mixing angle {\theta}13 allows experimental analysis in a manner which explicitly exhibits appearance and disappearance dependencies on additional parameters associated with mass-hierarchy, CP violation, and any non-maximal {\theta}23. These current and near-future experiments begin the era of precision accelerator long-baseline measurements and lay the framework within which future experimental results will be interpreted.Comment: 41 pages, 36 figures, submitted to New Journal of Physic

    Order-disorder oscillations in exciton-polariton superfluids

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    The dynamics of an exciton-polariton superfluid resonantly pumped in a semiconductor microcavity are investigated by mean-field theory. Modulational instability develops into crystalline order and then ordered and disordered states alternately form. A supersolid-like state is also found, in which superflow coexists with crystalline order at rest.Comment: 5 pages, 3 figures, 6 movie

    Anisotropic s-wave superconductivity in single crystals CaAlSi from penetration depth measurements

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    In- and out-of-plane London penetration depths were measured in single crystals CaAlSi (T_{c}=6.2 K and 7.3 K) using a tunnel-diode resonator. A full 3D BCS analysis of the superfluid density is consistent with a prolate spheroidal gap, with a weak-coupling BCS value in the ab-plane and stronger coupling along the c-axis. The gap anisotropy was found to significantly decrease for higher T_{c} samples.Comment: 4 page

    Critical phase of a magnetic hard hexagon model on triangular lattice

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    We introduce a magnetic hard hexagon model with two-body restrictions for configurations of hard hexagons and investigate its critical behavior by using Monte Carlo simulations and a finite size scaling method for discreate values of activity. It turns out that the restrictions bring about a critical phase which the usual hard hexagon model does not have. An upper and a lower critical value of the discrete activity for the critical phase of the newly proposed model are estimated as 4 and 6, respectively.Comment: 11 pages, 8 Postscript figures, uses revtex.st

    MHD Simulation of The Inner Galaxy with Radiative Cooling and Heating

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    We investigate the role of magnetic field on the gas dynamics in the Galactic bulge region by three dimensional simulations with radiative cooling and heating. While high-temperature corona with T>106 KT>10^6\ {\rm K} is formed in the halo regions, the temperature near the Galactic plane is 104 K\lesssim 10^4\ {\rm K} following the thermal equilibrium curve determined by the radiative cooling and heating. Although the thermal energy of the interstellar gas is lost by radiative cooling, the saturation level of the magnetic field strength does not significantly depend on the radiative cooling and heating. The magnetic field strength is amplified to 10 μG10\ {\rm \mu G} on average, and reaches several hundred μG{\rm \mu G} locally. We find the formation of magnetically dominated regions at mid-latitudes in the case with the radiative cooling and heating, which is not seen in the case without radiative effect. The vertical thickness of the mid-latitude regions is 50150 pc50-150\ {\rm pc} at the radial location of 0.40.8 kpc0.4-0.8 \ {\rm kpc} from the Galactic center, which is comparable to the observed vertical distribution of neutral atomic gas. When we take the average of different components of energy density integrated over the Galactic bulge region, the magnetic energy is comparable to the thermal energy. We conclude that the magnetic field plays a substantial role in controlling the dynamical and thermal properties of the Galactic bulge region.Comment: Submitted to ApJ; 21 pages, 18 figures 3 tables. Comment are welcom

    Evidence for field-induced excitations in low-temperature thermal conductivity of Bi_2Sr_2CaCu_2O_8

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    The thermal conductivity ,κ\kappa, of Bi_2Sr_2CaCu_2O_8 was studied as a function of magnetic field. Above 5 K, after an initial decrease, κ(H)\kappa(H) presents a kink followed by a plateau, as recently reported by Krishana et al.. By contrast, below 1K, the thermal conductivity was found to \emph{increase} with increasing field. This behavior is indicative of a finite density of states and is not compatible with the existence of a field-induced fully gapped dx2y2+idxyd_{x^{2}-y^{2}}+id_{xy} state which was recently proposed to describe the plateau regime. Our low-temperature results are in agreement with recent works predicting a field-induced enhancement of thermal conductivity by Doppler shift of quasi-particle spectrum.Comment: 4 pages including 4 eps figures, submitted to Phys. Rev. Let

    Noiseless Collective Motion out of Noisy Chaos

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    We consider the effect of microscopic external noise on the collective motion of a globally coupled map in fully desynchronized states. Without the external noise a macroscopic variable shows high-dimensional chaos distinguishable from random motion. With the increase of external noise intensity, the collective motion is successively simplified. The number of effective degrees of freedom in the collective motion is found to decrease as logσ2-\log{\sigma^2} with the external noise variance σ2\sigma^2. It is shown how the microscopic noise can suppress the number of degrees of freedom at a macroscopic level.Comment: 9 pages RevTex file and 4 postscript figure

    Density matrix renormalization group for the Berezinskii-Kosterlitz-Thouless transition of the 19-vertex model

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    We embody the density matrix renormalization group (DMRG) method for the 19-vertex model on a square lattice in order to investigate the Berezinskii-Kosterlitz-Thouless transition. Elements of the transfer matrix of the 19-vertex model are classified in terms of the total value of arrows in one layer of the square lattice. By using this classification, we succeed to reduce enormously the dimension of the matrix which has to be diagonalized in the DMRG method. We apply our method to the 19-vertex model with the interaction K=1.0866K=1.0866 and obtain c=1.006(1)c=1.006(1) for the conformal anomaly. PACS. 05.90.+m, 02.70.-cComment: RevTeX style, 20 pages, 12 figure

    Energetics of Forced Thermal Ratchet

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    Molecular motors are known to have the high efficiency of energy transformation in the presence of thermal fluctuation. Motivated by the surprising fact, recent studies of thermal ratchet models are showing how and when work should be extracted from non-equilibrium fluctuations. One of the important finding was brought by Magnasco where he studied the temperature dependence on the fluctuation-induced current in a ratchet (multistable) system and showed that the current can generically be maximized in a finite temperature. The interesting finding has been interpreted that thermal fluctuation is not harmful for the fluctuation-induced work and even facilitates its efficiency. We show, however, this interpretation turns out to be incorrect as soon as we go into the realm of the energetics [Sekimoto,J.Phys.Soc.Jpn.66,1234-1237(1997)]: the efficiency of energy transformation is not maximized at finite temperature, even in the same system that Magnasco considered. The maximum efficiency is realized in the absence of thermal fluctuation. The result presents an open problem whether thermal fluctuation could facilitate the efficiency of energetic transformation from force-fluctuation into work.Comment: 3pages, 4sets of figure
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