1,554 research outputs found

    Quark-lepton complementarity revisited

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    We reexamine the quark-lepton complementarity (QLC) in nine angle-phase parametrizations with the latest result of a large lepton mixing angle ϑ13\vartheta_{13} from the T2K, MINOS and Double Chooz experiments. We find that there are still two QLC relations satisfied in P1, P4 and P6 parametrizations, whereas only one QLC relation holds in P2, P3, P5 and P9 parametrizations separately. We also work out the corresponding reparametrization-invariant forms of the QLC relations and check the resulting expressions with the experimental data. The results can be viewed as a check of the validity of the QLC relations, as well as a new perspective into the issue of seeking for the connection between quarks and leptons.Comment: 5 Latex pages, 2 tables. Final version for publication in PR

    Constraining the Mass of the Photon with Gamma-Ray Bursts

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    One of the cornerstones of modern physics is Einstein's special relativity, with its constant speed of light and zero photon mass assumptions. Constraint on the rest mass m_{\gamma} of photons is a fundamental way to test Einstein's theory, as well as other essential electromagnetic and particle theories. Since non-zero photon mass can give rise to frequency-(or energy-) dependent dispersions, measuring the time delay of photons with different frequencies emitted from explosive astrophysical events is an important and model-independent method to put such a constraint. The cosmological gamma-ray bursts (GRBs), with short time scales, high redshifts as well as broadband prompt and afterglow emissions, provide an ideal testbed for m_{\gamma} constraints. In this paper we calculate the upper limits of the photon mass with GRB early time radio afterglow observations as well as multi-band radio peaks, thus improve the results of Schaefer (1999) by nearly half an order of magnitude.Comment: 25 pages, 2 tables, Accepted by Journal of High Energy Astrophysic

    Lifshitz Scaling Effects on Holographic Superconductors

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    Via numerical and analytical methods, the effects of the Lifshitz dynamical exponent zz on holographic superconductors are studied in some detail, including ss wave and pp wave models. Working in the probe limit, we find that the behaviors of holographic models indeed depend on concrete value of zz. We obtain the condensation and conductivity in both Lifshitz black hole and soliton backgrounds with general zz. For both ss wave and pp wave models in the black hole backgrounds, as zz increases, the phase transition becomes more difficult and the growth of conductivity is suppressed. For the Lifshitz soliton backgrounds, when zz increases (z=1, 2, 3z=1,~2,~3), the critical chemical potential decreases in the ss wave cases but increases in the pp wave cases. For pp wave models in both Lifshitz black hole and soliton backgrounds, the anisotropy between the AC conductivity in different spatial directions is suppressed when zz increases. The analytical results uphold the numerical results.Comment: Typos corrected; Footnote added; References added; To be published in Nuclear Physics

    Five-dimensional generalized f(R)f(R) gravity with curvature-matter coupling

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    The generalized f(R)f(R) gravity with curvature-matter coupling in five-dimensional (5D) spacetime can be established by assuming a hypersurface-orthogonal spacelike Killing vector field of 5D spacetime, and it can be reduced to the 4D formulism of FRW universe. This theory is quite general and can give the corresponding results to the Einstein gravity, f(R)f(R) gravity with both no-coupling and non-minimal coupling in 5D spacetime as special cases, that is, we would give the some new results besides previous ones given by Ref.\cite{60}. Furthermore, in order to get some insight into the effects of this theory on the 4D spacetime, by considering a specific type of models with f1(R)=f2(R)=αRmf_{1}(R)=f_{2}(R)=\alpha R^{m} and B(Lm)=Lm=ρB(L_{m})=L_{m}=-\rho, we not only discuss the constraints on the model parameters mm, nn, but also illustrate the evolutionary trajectories of the scale factor a(t)a(t), the deceleration parameter q(t)q(t) and the scalar field ϵ(t)\epsilon(t), ϕ(t)\phi(t) in the reduced 4D spacetime. The research results show that this type of f(R)f(R) gravity models given by us could explain the current accelerated expansion of our universe without introducing dark energy.Comment: arXiv admin note: text overlap with arXiv:0912.4581, arXiv:gr-qc/0411066 by other author

    Masking: A New Perspective of Noisy Supervision

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    It is important to learn various types of classifiers given training data with noisy labels. Noisy labels, in the most popular noise model hitherto, are corrupted from ground-truth labels by an unknown noise transition matrix. Thus, by estimating this matrix, classifiers can escape from overfitting those noisy labels. However, such estimation is practically difficult, due to either the indirect nature of two-step approaches, or not big enough data to afford end-to-end approaches. In this paper, we propose a human-assisted approach called Masking that conveys human cognition of invalid class transitions and naturally speculates the structure of the noise transition matrix. To this end, we derive a structure-aware probabilistic model incorporating a structure prior, and solve the challenges from structure extraction and structure alignment. Thanks to Masking, we only estimate unmasked noise transition probabilities and the burden of estimation is tremendously reduced. We conduct extensive experiments on CIFAR-10 and CIFAR-100 with three noise structures as well as the industrial-level Clothing1M with agnostic noise structure, and the results show that Masking can improve the robustness of classifiers significantly.Comment: NIPS 2018 camera-ready versio

    Lifshitz effects on holographic pp-wave superfluid

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    In the probe limit, we numerically build a holographic pp-wave superfluid model in the four-dimensional Lifshitz black hole coupled to a Maxwell-complex vector field. We observe the rich phase structure and find that the Lifshitz dynamical exponent zz contributes evidently to the effective mass of the matter field and dimension of the gravitational background. Concretely, we obtain the Cave of Winds appeared only in the five-dimensional anti-de Sitter~(AdS) spacetime, and the increasing zz hinders not only the condensate but also the appearance of the first-order phase transition. Furthermore, our results agree with the Ginzburg-Landau results near the critical temperature. In addition, the previous AdS superfluid model is generalized to the Lifshitz spacetime.Comment: 14 pages,5 figures, and 1 table, accepted by Phys. Lett.

    Multi-Dimensional Recommendation Scheme for Social Networks Considering a User Relationship Strength Perspective

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    Developing a computational method based on user relationship strength for multi-dimensional recommendation is a significant challenge. The traditional recommendation methods have relatively low accuracy because they lack considering information from the perspective of user relationship strength into the recommendation algorithm. User relationship strength reflects the degree of closeness between two users, which can make the recommendation system more efficient between users in pairs. This paper proposes a multi-dimensional comprehensive recommendation method based on user relationship strength. We take three main factors into consideration, including the strength of user relationship, the similarity of entities, and the degree of user interest. First, we introduce a novel method to generate a user candidate set and an entity candidate set by calculating the relationship strength between two users and the similarity between two entities. Then, the algorithm will calculate the user interest degree of each user in the user candidate set to each entity in the entity candidate set, if the user interest degree is larger than or equal to a threshold, this particular entity will be recommended to this user. The performance of the proposed method was verified based on the real-world social network dataset and the e-commerce website dataset, and the experimental result suggests that this method can improve the recommendation accuracy
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