5,202 research outputs found

    Topology in thermodynamics of regular black strings with Kaluza-Klein reduction

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    We study the topological defects in the thermodynamics of regular black strings (from a four-dimensional perspective) that is symmetric under the double Wick rotation and constructed in the high-dimensional spacetime with an extra dimension compactified on a circle. We observe that the thermodynamic phases of regular black strings can be topologically classified by the positive and negative winding numbers (at the defects) which correspond to the thermodynamically stable and unstable branches. This topological classification implies a phase transition due to the decay of a thermodynamically unstable regular black string to another which is thermodynamically stable. We confirm these topological properties of the thermodynamics of regular black strings by investigating their free energy, heat capacity, and Ruppeiner scalar curvature of the state space. The Ruppeiner scalar curvature of regular black strings is found to be always negative, implying that the interactions among the microstructures of regular black strings are only attractive.Comment: 21 pages, 10 figure

    Well-Rounded ideal lattices of cyclic cubic and quartic fields

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    In this paper, we find criteria for when cyclic cubic and cyclic quartic fields have well-rounded ideal lattices. We show that every cyclic cubic field has at least one well-rounded ideal. We also prove that there exist families of cyclic quartic fields which have well-rounded ideals and explicitly construct their minimal bases. In addition, for a given prime number pp, if a cyclic quartic field has a unique prime ideal above pp, then we provide the necessary and sufficient conditions for that ideal to be well-rounded. Moreover, in cyclic quartic fields, we provide the prime decomposition of all odd prime numbers and construct an explicit integral basis for every prime ideal.Comment: 26 page

    Well-Rounded Twists of Ideal Lattices from Imaginary Quadratic Fields

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    In this paper, we investigate the properties of well-rounded twists of a given ideal lattice of an imaginary quadratic field KK. We show that every ideal lattice II of KK has at least one well-rounded twist lattice. Moreover, we provide an explicit algorithm to compute all well-rounded twists of II.Comment: 24 page

    La fonction de partition de Minc et une conjecture de Segal pour certains spectres de Thom

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    On construit dans cet article une résolution injective minimale dans la catégorie \U des modules instables sur l'algèbre de Steenrod modulo 22, de la cohomologie de certains spectres obtenus à partir de l'espace de Thom du fibré, associé à la représentation régulière réduite du groupe abélien élémentaire (Z/2)n(\Z/2)^n, au dessus de l'espace B(Z/2)nB(\Z/2)^n. Les termes de la résolution sont des produits tensoriels de modules de Brown-Gitler J(k)J(k) et de modules de Steinberg LnL_n introduits par S. Mitchell et S. Priddy. Ces modules sont injectifs d'après J. Lannes et S. Zarati, de plus ils sont indécomposables. L'existence de cette résolution avait été conjecturée par Jean Lannes et le deuxième auteur. La principale indication soutenant cette conjecture était un résultat combinatoire de G. Andrews : la somme alternée des séries de Poincaré des modules considérées est nulle
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