421 research outputs found

    Renormalization group trajectories from resonance factorized S-matrices

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    We propose and investigate a large class of models possessing resonance factorized S-matrices. The associated Casimir energy describes a rich pattern of renormalization group trajectories related to flows in the coset models based on the simply laced Lie Algebras. From a simplest resonance S-matrix, satisfying the ``ϕ3\phi^3-property'', we predict new flows in non-unitary minimal models.Comment: (7 pages) (no figures included

    LunaNet: a Flexible and Extensible Lunar Exploration Communications and Navigation Infrastructure

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    NASA has set the ambitious goal of establishing a sustainable human presence on the Moon. Diverse commercial and international partners are engaged in this effort to catalyze scientific discovery, lunar resource utilization and economic development on both the Earth and at the Moon. Lunar development will serve as a critical proving ground for deeper exploration into the solar system. Space communications and navigation infrastructure will play an integral part in realizing this goal. This paper provides a high-level description of an extensible and scalable lunar communications and navigation architecture, known as LunaNet. LunaNet is a services network to enable lunar operations. Three LunaNet service types are defined: networking services, position, navigation and timing services, and science utilization services. The LunaNet architecture encompasses a wide variety of topology implementations, including surface and orbiting provider nodes. In this paper several systems engineering considerations within the service architecture are highlighted. Additionally, several alternative LunaNet instantiations are presented. Extensibility of the LunaNet architecture to the solar system internet is discussed

    Solar Flare Impulsive Phase Observations from SDO and Other Observatories

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    With the start of normal operations of the Solar Dynamics Observatory in May 2010, the Extreme ultraviolet Variability Experiment (EVE) and the Atmospheric Imaging Assembly (AIA) have been returning the most accurate solar XUV and EUV measurements every 10 and 12 seconds, respectively, at almost 100% duty cycle. The focus of the presentation will be the solar flare impulsive phase observations provided by EVE and AIA and what these observations can tell us about the evolution of the initial phase of solar flares. Also emphasized throughout is how simultaneous observations with other instruments, such as RHESSI, SOHO-CDS, and HINODE-EIS, will help provide a more complete characterization of the solar flares and the evolution and energetics during the impulsive phase. These co-temporal observations from the other solar instruments can provide information such as extending the high temperature range spectra and images beyond that provided by the EUV and XUV wavelengths, provide electron density input into the lower atmosphere at the footpoints, and provide plasma flows of chromospheric evaporation, among other characteristics

    Universal amplitudes in the FSS of three-dimensional spin models

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    In a MC study using a cluster update algorithm we investigate the finite-size scaling (FSS) of the correlation lengths of several representatives of the class of three-dimensional classical O(n) symmetric spin models on a column geometry. For all considered models we find strong evidence for a linear relation between FSS amplitudes and scaling dimensions when applying antiperiodic instead of periodic boundary conditions across the torus. The considered type of scaling relation can be proven analytically for systems on two-dimensional strips with periodic bc using conformal field theoryComment: 4 pages, RevTex, uses amsfonts.sty, 3 Figure

    Fermionic representations for characters of M(3,t), M(4,5), M(5,6) and M(6,7) minimal models and related Rogers-Ramanujan type and dilogarithm identities

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    Characters and linear combinations of characters that admit a fermionic sum representation as well as a factorized form are considered for some minimal Virasoro models. As a consequence, various Rogers-Ramanujan type identities are obtained. Dilogarithm identities producing corresponding effective central charges and secondary effective central charges are derived. Several ways of constructing more general fermionic representations are discussed.Comment: 14 pages, LaTex; minor correction

    The State of Self-Organized Criticality of the Sun During the Last 3 Solar Cycles. I. Observations

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    We analyze the occurrence frequency distributions of peak fluxes PP, total fluxes EE, and durations TT of solar flares over the last three solar cycles (during 1980--2010) from hard X-ray data of HXRBS/SMM, BATSE/CGRO, and RHESSI. From the synthesized data we find powerlaw slopes with mean values of αP=1.72±0.08\alpha_P=1.72\pm0.08 for the peak flux, αE=1.60±0.14\alpha_E=1.60\pm0.14 for the total flux, and αT=1.98±0.35\alpha_T=1.98\pm0.35 for flare durations. We find a systematic anti-correlation of the powerlaw slope of peak fluxes as a function of the solar cycle, varying with an approximate sinusoidal variation αP(t)=α0+Δαcos[2π(tt0)/Tcycle]\alpha_P(t)=\alpha_0+\Delta \alpha \cos{[2\pi (t-t_0)/T_{cycle}]}, with a mean of α0=1.73\alpha_0=1.73, a variation of Δα=0.14\Delta \alpha =0.14, a solar cycle period Tcycle=12.6T_{cycle}=12.6 yrs, and a cycle minimum time t0=1984.1t_0=1984.1. The powerlaw slope is flattest during the maximum of a solar cycle, which indicates a higher magnetic complexity of the solar corona that leads to an overproportional rate of powerful flares.Comment: subm. to Solar Physic

    Marginal Extended Perturbations in Two Dimensions and Gap-Exponent Relations

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    The most general form of a marginal extended perturbation in a two-dimensional system is deduced from scaling considerations. It includes as particular cases extended perturbations decaying either from a surface, a line or a point for which exact results have been previously obtained. The first-order corrections to the local exponents, which are functions of the amplitude of the defect, are deduced from a perturbation expansion of the two-point correlation functions. Assuming covariance under conformal transformation, the perturbed system is mapped onto a cylinder. Working in the Hamiltonian limit, the first-order corrections to the lowest gaps are calculated for the Ising model. The results confirm the validity of the gap-exponent relations for the perturbed system.Comment: 11 pages, Plain TeX, eps

    Kronecker's Double Series and Exact Asymptotic Expansion for Free Models of Statistical Mechanics on Torus

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    For the free models of statistical mechanics on torus, exact asymptotic expansions of the free energy, the internal energy and the specific heat in the vicinity of the critical point are found. It is shown that there is direct relation between the terms of the expansion and the Kronecker's double series. The latter can be expressed in terms of the elliptic theta-functions in all orders of the asymptotic expansion.Comment: REVTeX, 22 pages, this is expanded version which includes exact asymptotic expansions of the free energy, the internal energy and the specific hea

    Thin Animals

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    Lattice animals provide a discretized model for the theta transition displayed by branched polymers in solvent. Exact graph enumeration studies have given some indications that the phase diagram of such lattice animals may contain two collapsed phases as well as an extended phase. This has not been confirmed by studies using other means. We use the exact correspondence between the q --> 1 limit of an extended Potts model and lattice animals to investigate the phase diagram of lattice animals on phi-cubed random graphs of arbitrary topology (``thin'' random graphs). We find that only a two phase structure exists -- there is no sign of a second collapsed phase. The random graph model is solved in the thermodynamic limit by saddle point methods. We observe that the ratio of these saddle point equations give precisely the fixed points of the recursion relations that appear in the solution of the model on the Bethe lattice by Henkel and Seno. This explains the equality of non-universal quantities such as the critical lines for the Bethe lattice and random graph ensembles.Comment: Latex, 10 pages plus 6 ps/eps figure

    On the Classification of Diagonal Coset Modular Invariants

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    We relate in a novel way the modular matrices of GKO diagonal cosets without fixed points to those of WZNW tensor products. Using this we classify all modular invariant partition functions of su(3)ksu(3)1/su(3)k+1su(3)_k\oplus su(3)_1/su(3)_{k+1} for all positive integer level kk, and su(2)ksu(2)/su(2)k+su(2)_k\oplus su(2)_\ell/su(2)_{k+\ell} for all kk and infinitely many \ell (in fact, for each kk a positive density of \ell). Of all these classifications, only that for su(2)ksu(2)1/su(2)k+1su(2)_k\oplus su(2)_1/su(2)_{k+1} had been known. Our lists include many new invariants.Comment: 24 pp (plain tex
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