3,837 research outputs found

    Remarks on the structure constants of the Verlinde algebra associated to sl3sl_3

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    The structure constants Nλ,μμ+νN_{\lambda, \mu}^{\mu+\nu} of the sl2sl_2 Verlinde algebra as functions of μ\mu either vanish or can be expressed after a change of variable as the weight function of an irreducible representation of sl2sl_2. We give a similar formula in the sl3sl_3 case.Comment: 5 pages, AmsTeX, 1 figure available on reques

    Alpha cluster condensation in 12C and 16O

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    A new α\alpha-cluster wave function is proposed which is of the α\alpha-particle condensate type. Applications to 12^{12}C and 16^{16}O show that states of low density close to the 3 resp. 4 α\alpha-particle threshold in both nuclei are possibly of this kind. It is conjectured that all self-conjugate 4nn nuclei may show similar features.Comment: 4 pages, 2 tables, 2 figure

    Bound-State Variational Wave Equation For Fermion Systems In QED

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    We present a formulation of the Hamiltonian variational method for QED which enables the derivation of relativistic few-fermion wave equation that can account, at least in principle, for interactions to any order of the coupling constant. We derive a relativistic two-fermion wave equation using this approach. The interaction kernel of the equation is shown to be the generalized invariant M-matrix including all orders of Feynman diagrams. The result is obtained rigorously from the underlying QFT for arbitrary mass ratio of the two fermions. Our approach is based on three key points: a reformulation of QED, the variational method, and adiabatic hypothesis. As an application we calculate the one-loop contribution of radiative corrections to the two-fermion binding energy for singlet states with arbitrary principal quantum number nn, and l=J=0l =J=0. Our calculations are carried out in the explicitly covariant Feynman gauge.Comment: 26 page

    A reduced subduction graph and higher multiplicity in S_n transformation coefficients

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    Transformation coefficients between {\it standard} bases for irreducible representations of the symmetric group SnS_n and {\it split} bases adapted to the Sn1×Sn2⊂SnS_{n_1} \times S_{n_2} \subset S_n subgroup (n1+n2=nn_1 +n_2 = n) are considered. We first provide a \emph{selection rule} and an \emph{identity rule} for the subduction coefficients which allow to decrease the number of unknowns and equations arising from the linear method by Pan and Chen. Then, using the {\it reduced subduction graph} approach, we may look at higher multiplicity instances. As a significant example, an orthonormalized solution for the first multiplicity-three case, which occurs in the decomposition of the irreducible representation [4,3,2,1][4,3,2,1] of S10S_{10} into [3,2,1]⊗[3,1][3,2,1] \otimes [3,1] of S6×S4S_6 \times S_4, is presented and discussed.Comment: 12 pages, 1 figure, iopart class, Revisited version (several typographical errors have been corrected). Accepted for publication in J. Phys. A: Math. Ge

    Matrix Models, Monopoles and Modified Moduli

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    Motivated by the Dijkgraaf-Vafa correspondence, we consider the matrix model duals of N=1 supersymmetric SU(Nc) gauge theories with Nf flavors. We demonstrate via the matrix model solutions a relation between vacua of theories with different numbers of colors and flavors. This relation is due to an N=2 nonrenormalization theorem which is inherited by these N=1 theories. Specializing to the case Nf=Nc, the simplest theory containing baryons, we demonstrate that the explicit matrix model predictions for the locations on the Coulomb branch at which monopoles condense are consistent with the quantum modified constraints on the moduli in the theory. The matrix model solutions include the case that baryons obtain vacuum expectation values. In specific cases we check explicitly that these results are also consistent with the factorization of corresponding Seiberg-Witten curves. Certain results are easily understood in terms of M5-brane constructions of these gauge theories.Comment: 27 pages, LaTeX, 2 figure

    Cube law, condition factor and weight-length relationships: history, meta-analysis and recommendations

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    This study presents a historical review, a meta-analysis, and recommendations for users about weight–length relationships, condition factors and relative weight equations. The historical review traces the developments of the respective concepts. The meta-analysis explores 3929 weight–length relationships of the type W = aLb for 1773 species of fishes. It shows that 82% of the variance in a plot of log a over b can be explained by allometric versus isometric growth patterns and by different body shapes of the respective species. Across species median b = 3.03 is significantly larger than 3.0, thus indicating a tendency towards slightly positive-allometric growth (increase in relative body thickness or plumpness) in most fishes. The expected range of 2.5 < b < 3.5 is confirmed. Mean estimates of b outside this range are often based on only one or two weight–length relationships per species. However, true cases of strong allometric growth do exist and three examples are given. Within species, a plot of log a vs b can be used to detect outliers in weight–length relationships. An equation to calculate mean condition factors from weight–length relationships is given as Kmean = 100aLb−3. Relative weight Wrm = 100W/(amLbm) can be used for comparing the condition of individuals across populations, where am is the geometric mean of a and bm is the mean of b across all available weight–length relationships for a given species. Twelve recommendations for proper use and presentation of weight–length relationships, condition factors and relative weight are given

    Lie group weight multiplicities from conformal field theory

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    Dominant weight multiplicities of simple Lie groups are expressed in terms of the modular matrices of Wess-Zumino-Witten conformal field theories, and related objects. Symmetries of the modular matrices give rise to new relations among multiplicities. At least for some Lie groups, these new relations are strong enough to completely fix all multiplicities.Comment: 12 pages, Plain TeX, no figure
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