192,209 research outputs found

    Slideshow: Luminaries and Rising Stars Light Up Global Heritage Hall

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    LIVE@RWU Concert Series welcomes Freddy Cole, Aaron Diehl in inaugural season

    Reply to Comment on "Casimir force in the O(n)O(n\to\infty) model with free boundary conditions"

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    The proceeding comment raises a few points concerning our paper Dantchev \textit{et al.}, Phys. Rev. E. {\bf 89}, 042116 (2014). In this reply we stress that while Refs. Diehl \textit{et al.} EPL {\bf 100}, 10004 (2012) and Phys. Rev. E. {\bf 89}, 062123 (2014) use three different models to study the the Casimir force for the O(n)O(n \rightarrow \infty) model with free boundary conditions we study a single model over the entire range of temperatures, from above the bulk critical temperature, TcT_c, to absolute temperatures down to T=0T=0. The use of a single model renders more transparent the crossover from effects dominated by critical fluctuations in the vicinity of the bulk transition temperature to effects controlled by Goldstone modes at low temperatures. Contrary to the assertion in the comment, we make no claim for the superiority of our model over any of those considered by Diehl \textit{et al}. We also present additional evidence supporting our conclusion in Dantchev \textit{et al.}, Phys. Rev. E. {\bf 89}, 042116 (2014) that the temperature range in which our low-temperature analytical expansion for the Casimir force increases as LL grows and remains accurate for values of the ratio T/TcT/T_c that become closer and closer to unity, while TT remains well outside of the critical region.Comment: 3 pages, 1 tabl

    Representing disease courses: An application of the Neurological Disease Ontology to Multiple Sclerosis Typology

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    The Neurological Disease Ontology (ND) is being developed to provide a comprehensive framework for the representation of neurological diseases (Diehl et al., 2013). ND utilizes the model established by the Ontology for General Medical Science (OGMS) for the representation of entities in medicine and disease (Scheuermann et al., 2009). The goal of ND is to include information for each disease concerning its molecular, genetic, and environmental origins, the processes involved in its etiology and realization, as well as its clinical presentation including signs and symptoms

    Reply to "Comment on Renormalization group picture of the Lifshitz critical behaviors"

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    We reply to a recent comment by Diehl and Shpot (cond-mat/0305131) criticizing a new approach to the Lifshitz critical behavior just presented (M. M. Leite Phys. Rev. B 67, 104415(2003)). We show that this approach is free of inconsistencies in the ultraviolet regime. We recall that the orthogonal approximation employed to solve arbitrary loop diagrams worked out at the criticized paper even at three-loop level is consistent with homogeneity for arbitrary loop momenta. We show that the criticism is incorrect.Comment: RevTex, 6 page

    Critical Casimir amplitudes for nn-component ϕ4\phi^4 models with O(n)-symmetry breaking quadratic boundary terms

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    Euclidean nn-component ϕ4\phi^4 theories whose Hamiltonians are O(n) symmetric except for quadratic symmetry breaking boundary terms are studied in films of thickness LL. The boundary terms imply the Robin boundary conditions nϕα=c˚α(j)ϕα\partial_n\phi_\alpha =\mathring{c}^{(j)}_\alpha \phi_\alpha at the boundary planes Bj=1,2\mathfrak{B}_{j=1,2} at z=0z=0 and z=Lz=L. Particular attention is paid to the cases in which mjm_j of the nn variables c˚α(j)\mathring{c}^{(j)}_\alpha take the special value c˚mj-sp\mathring{c}_{m_j\text{-sp}} corresponding to critical enhancement while the remaining ones are subcritically enhanced. Under these conditions, the semi-infinite system bounded by Bj\mathfrak{B}_j has a multicritical point, called mjm_j-special, at which an O(mj)O(m_j) symmetric critical surface phase coexists with the O(n) symmetric bulk phase, provided dd is sufficiently large. The LL-dependent part of the reduced free energy per area behaves as ΔC/Ld1\Delta_C/L^{d-1} as LL\to\infty at the bulk critical point. The Casimir amplitudes ΔC\Delta_C are determined for small ϵ=4d\epsilon=4-d in the general case where mc,cm_{c,c} components ϕα\phi_\alpha are critically enhanced at both boundary planes, mc,D+mD,cm_{c,D} + m_{D,c} components are enhanced at one plane but satisfy asymptotic Dirichlet boundary conditions at the respective other, and the remaining mD,Dm_{D,D} components satisfy asymptotic Dirichlet boundary conditions at both Bj\mathfrak{B}_j. Whenever mc,c>0m_{c,c}>0, these expansions involve integer and fractional powers ϵk/2\epsilon^{k/2} with k3k\ge 3 (mod logarithms). Results to O(ϵ3/2)O(\epsilon^{3/2}) for general values of mc,cm_{c,c}, mc,D+mD,cm_{c,D}+m_{D,c}, and mD,Dm_{D,D} are used to estimate the ΔC\Delta_C of 3D Heisenberg systems with surface spin anisotropies when (mc,c,mc,D+mD,c)=(1,0)(m_{c,c}, m_{c,D}+ m_{D,c}) = (1,0), (0,1)(0,1), and (1,1)(1,1).Comment: Latex source file with 5 eps files; version with minor amendments and corrected typo

    A study of the pitching moments and the stability characteristics of monoplanes

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    This note presents a study of the pitching moments and the stability characteristics of monoplanes. Expressions for the pitching-moment coefficient and the Diehl stability coefficient for the monoplane are developed, suitable for the use of airplane designers. The effective difference between the high-wing and low-wing types is portrayed and discussed. Comparisons between experimental and computed values are made. Charts for use in the solution of numerical values of the pitching-moment and stability coefficients are presented

    Energy Momentum Tensor in Conformal Field Theories Near a Boundary

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    The requirements of conformal invariance for the two point function of the energy momentum tensor in the neighbourhood of a plane boundary are investigated, restricting the conformal group to those transformations leaving the boundary invariant. It is shown that the general solution may contain an arbitrary function of a single conformally invariant variable vv, except in dimension 2. The functional dependence on vv is determined for free scalar and fermion fields in arbitrary dimension dd and also to leading order in the \vep expansion about d=4d=4 for the non Gaussian fixed point in ϕ4\phi^4 theory. The two point correlation function of the energy momentum tensor and a scalar field is also shown to have a unique expression in terms of vv and the overall coefficient is determined by the operator product expansion. The energy momentum tensor on a general curved manifold is further discussed by considering variations of the metric. In the presence of a boundary this procedure naturally defines extra boundary operators. By considering diffeomorphisms these are related to components of the energy momentum tensor on the boundary. The implications of Weyl invariance in this framework are also derived.Comment: 22 pages, TeX with epsf.tex, DAMTP/93-1. (original uuencoded file was corrupted enroute - resubmitted version has uuencoded figures pasted to the ended of the Plain TeX file

    Generalized parton distributions: recent results

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    I review progress on selected issues connected with generalized parton distributions. Topics range from the description of hard exclusive reactions to the spatial distribution of quarks in the nucleon and the contribution of their orbital angular momentum to the nucleon spin.Comment: 9 pages, 5 figures. To appear in the proceedings of the Particles and Nuclei International Conference (PANIC 05), Santa Fe, NM, USA, 24-28 Oct 200

    Gamma-ray line measurements from supernova explosions

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    Gamma ray lines are expected to be emitted as part of the afterglow of supernova explosions, because radioactive decay of freshly synthesised nuclei occurs. Significant radioactive gamma ray line emission is expected from 56Ni and 44Ti decay on time scales of the initial explosion (56Ni, tau~days) and the young supernova remnant (44Ti,tau~90 years). Less specific, and rather informative for the supernova population as a whole, are lessons from longer lived isotopes such as 26Al and 60Fe. From isotopes of elements heavier than iron group elements, any interesting gamma-ray line emission is too faint to be observable. Measurements with space-based gamma-ray telescopes have obtained interesting gamma ray line emissions from two core collapse events, Cas A and SN1987A, and one thermonuclear event, SN2014J. We discuss INTEGRAL data from all above isotopes, including all line and continuum signatures from these two objects, and the surveys for more supernovae, that have been performed by gamma ray spectrometry. Our objective here is to illustrate what can be learned from gamma-ray line emission properties about the explosions and their astrophysics.Comment: 7 pages, 4 figures. IAU Symposium 331 "SN1987A 30 years after", La Reunion, Feb. 2017. Accepted for publication in IAU Conf Pro

    Well-posedness for a monotone solver for traffic junctions

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    In this paper we aim at proving well-posedness of solutions obtained as vanishing viscosity limits for the Cauchy problem on a traffic junction where mm incoming and nn outgoing roads meet. The traffic on each road is governed by a scalar conservation law ρh,t+fh(ρh)x=0 \rho_{h,t} + f_h(\rho_h)_x = 0, for h{1,,m+n}h\in \{1,\ldots, m+n\}. Our proof relies upon the complete description of the set of road-wise constant solutions and its properties, which is of some interest on its own. Then we introduce a family of Kruzhkov-type adapted entropies at the junction and state a definition of admissible solution in the same spirit as in \cite{diehl, ColomboGoatinConstraint, scontrainte, AC_transmission, germes}
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