77,817 research outputs found

    Magnetoconductivity in Weyl semimetals: Effect of chemical potential and temperature

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    We present the detailed analyses of magneto-conductivities in a Weyl semimetal within Born and self-consistent Born approximations. In the presence of the charged impurities, the linear magnetoresistance can happen when the charge carriers are mainly from the zeroth (n=0) Landau level. Interestingly, the linear magnetoresistance is very robust against the change of temperature, as long as the charge carriers mainly come from the zeroth Landau level. We denote this parameter regime as the high-field regime. On the other hand, the linear magnetoresistance disappears once the charge carriers from the higher Landau levels can provide notable contributions. Our analysis indicates that the deviation from the linear magnetoresistance is mainly due to the deviation of the longitudinal conductivity from the 1/B1/B behavior. We found two important features of the self-energy approximation: 1. a dramatic jump of σxx\sigma_{xx}, when the n=1n=1 Landau level begins to contribute charge carriers, which is the beginning point of the middle-field regime, when decreasing the external magnetic field from high field; 2. In the low-field regime σxx\sigma_{xx} shows a B5/3B^{-5/3} behavior and results the magnetoresistance ρxx\rho_{xx} to show a B1/3B^{1/3} behavior. The detailed and careful numerical calculation indicates that the self-energy approximation (including both the Born and the self-consistent Born approximations) does not explain the recent experimental observation of linear magnetoresistance in Weyl semimetals.Comment: The accepted version. Extending the previous version by including the discussions of self-consistent Born approximatio

    Sample Paths of the Solution to the Fractional-colored Stochastic Heat Equation

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    Let u = {u(t, x), t \in [0, T ], x \in R d } be the solution to the linear stochastic heat equation driven by a fractional noise in time with correlated spatial structure. We study various path properties of the process u with respect to the time and space variable, respectively. In particular, we derive their exact uniform and local moduli of continuity and Chung-type laws of the iterated logarithm

    Partial Hasse invariants on splitting models of Hilbert modular varieties

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    Let FF be a totally real field of degree gg, and let pp be a prime number. We construct gg partial Hasse invariants on the characteristic pp fiber of the Pappas-Rapoport splitting model of the Hilbert modular variety for FF with level prime to pp, extending the usual partial Hasse invariants defined over the Rapoport locus. In particular, when pp ramifies in FF, we solve the problem of lack of partial Hasse invariants. Using the stratification induced by these generalized partial Hasse invariants on the splitting model, we prove in complete generality the existence of Galois pseudo-representations attached to Hecke eigenclasses of paritious weight occurring in the coherent cohomology of Hilbert modular varieties mod\mathrm{mod} pmp^m, extending a previous result of M. Emerton and the authors which required pp to be unramified in FF.Comment: 24 pages, refereed version, index changed from the previous versio

    Fuck revisited.

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    This paper is a follow up to the investigation of McEnery, Baker and Hardie (2000) into the use of the word fuck in spoken British English. Both that paper and this are based on the British National Corpus. However, at the time of writing in 2000, the analysis of fuck in the written BNC had not been completed, hence the 2000 paper focussed on spoken English alone. In doing so, it explored the way fuck varied with respect to a range of meta-data encoded in the spoken BNC, principally age, sex and social class. We have now explored the written section of the BNC, and have explored the distribution of fuck with respect to a subset of the metadata encoded in the written BNC, namely domain, author gender, author age, audience gender, audience age, audience level, reception status, medium of text and date of creation. As some of these features have clear analogues in the spoken BNC (most clearly age and sex) comparisons between the work presented here and the earlier work on spoken English will be presented wherever possible. Throughout, unless otherwise stated, references to the frequency of usage of features in spoken language are taken from McEnery, Baker and Hardie (ibid)

    Laboratory Evaluation of Mefluidide Effects on Elongation of Hydrilla and Eurasian Watermilfoil

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    The potential of mefluidide (N-(2,4-dimethyl-5[[trifluromethyl) sulfonyl] amino] phenol) acetamide) to act as a submersed aquatic plant growth regulator was evaluated using a laboratory bioassay system. Main stem elongation of hydrilla (Hydrilla verticillata (L.f.) Royle) and Eurasian watermilfoil (Myriophyllum spicatum L.) was effectively reduced by mefluidide at low concentrations. The lowest effective concentration of mefluidide that reduced stem length in Eurasian watermilfoil (100 yg a.i./L) was 5 times lower than that for hydrilla (500 yg a.i./L). Short-term net photosynthetic rates of these plants were not affected by mefluidide at concentrations as high as 1000 yg a.i./L. The minimum exposure time required to maintain an inhibitory effect for at least 28 days at a concentration of 500 yg ai.i./L was 3 to 7 days for Eurasian watermilfoil and 7 to 14 days for hydrilla. The results suggest that mefluidide is a more effective growth regulator for Eurasian watermilfoil than hydrilla. Exogenously applied gibberellic acid (GA) did not completely overcome the inhibitory effect of mefluidide even when GA was added at a high concentration (10-5 M). In addition, the internodal lengths of stems treated with mefluidide were not reduced as they were when treated with gibberellin synthesis inhibitors. The reduction of main stem elongation by mefluidide appeared to be due to the inhibition of new cell and tissue development at the stem tip rather than from inhibition of GA biosynthesis

    Domains, text types, aspect marking and English-Chinese translation.

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    This paper uses an English-Chinese parallel corpus, an L1 Chinese comparable corpus, and an L1 Chinese reference corpus to examine how aspectual meanings in English are translated into Chinese and explore the effects of domains, text types and translation on aspect marking. We will show that while English and Chinese both mark aspect grammatically, the aspect system in the two languages differs considerably. Even though Chinese, as an aspect language, is rich in aspect markers, covert marking (LVM) is a frequent and important strategy in Chinese discourse. The distribution of aspect markers varies significantly across domain and text type. The study also sheds new light on the translation effect by contrasting aspect marking in translated Chinese texts and L1 Chinese texts
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