2,263 research outputs found

    Four-boson scale near a Feshbach resonance

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    We show that an independent four-body momentum scale μ(4)\mu_{(4)} drives the tetramer binding energy for fixed trimer energy (or three-body scale μ(3)\mu_{(3)}) and large scattering length (aa). The three- and four-body forces from the one-channel reduction of the atomic interaction near a Feshbach resonance disentangle μ(4)\mu_{(4)} and μ(3)\mu_{(3)}. The four-body independent scale is also manifested through a family of Tjon-lines, with slope given by μ(4)/μ(3)\mu_{(4)}/\mu_{(3)} for a−1=0a^{-1}=0. There is the possibility of a new renormalization group limit cycle due to the new scale

    Nonperturbative study of the two-frequency sine-Gordon model

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    The two-frequency sine-Gordon model is examined. The focus is mainly on the case when the ratio of the frequencies is 1/2, given the recent interest in the literature. We discuss the model both in a perturbative (form factor perturbation theory) and a nonperturbative (truncated conformal space approach) framework, and give particular attention to a phase transition conjectured earlier by Delfino and Mussardo. We give substantial evidence that the transition is of second order and that it is in the Ising universality class. Furthermore, we check the UV-IR operator correspondence and conjecture the phase diagram of the theory.Comment: Minor corrections, LaTeX2e, 39 pages, 26 figures (4 pslatex, 1 postscript and 21 eps

    Boundary form factors of the sinh-Gordon model with Dirichlet boundary conditions at the self-dual point

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    In this manuscript we present a detailed investigation of the form factors of boundary fields of the sinh-Gordon model with a particular type of Dirichlet boundary condition, corresponding to zero value of the sinh-Gordon field at the boundary, at the self-dual point. We follow for this the boundary form factor program recently proposed by Z. Bajnok, L. Palla and G. Takaks in hep-th/0603171, extending the analysis of the boundary sinh-Gordon model initiated there. The main result of the paper is a conjecture for the structure of all n-particle form factors of two particular boundary operators in terms of elementary symmetric polynomials in certain functions of the rapidity variables. In addition, form factors of boundary "descendant" fields have been constructedComment: 14 pages LaTex. Version to appear in J. Phys.

    The Scontrone turtles – A new insular testudinoid fauna from the late Miocene of the Central Mediterranean

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    We here describe a small turtle assemblage originating from the early Tortonian (late Miocene) palaeois-land of Scontrone, central Italy, a locality previously known mostly for its endemic mammals and giantbirds, which were otherwise shared only with the Gargano localities, another fossiliferous area belongingto the same palaeobioprovince. The fossil turtle remains from Scontrone are referred to the geoemydidMauremyssp. and a so far unidentified large-sized testudinid. The biogeographic origins of theScontrone insular chelonians are discussed. The Scontrone geoemydid adds to the known occurrencesofMauremysin the late Miocene of the Mediterranean. The Scontrone large tortoise represents the oldestknown Mediterranean insular testudinid, predating significantly the well-known Quaternary endemicisland tortoises of the area

    Isospin Constraints on the Parametric Coupling Model for Nuclear Matter

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    We make use of isospin constraints to study the parametric coupling model and the properties of asymmetric nuclear matter. Besides the usual constraints for nuclear matter - effective nucleon mass and the incompressibility at saturation density - and the neutron star constraints - maximum mass and radius - we have studied the properties related with the symmetry energy. These properties have constrained to a small range the parameters of the model. We have applied our results to study the thermodynamic instabilities in the liquid-gas phase transition as well as the neutron star configurations.Comment: 11 pages, 10 figure

    Form factors in the Bullough-Dodd related models: The Ising model in a magnetic field

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    We consider particular modification of the free-field representation of the form factors in the Bullough-Dodd model. The two-particles minimal form factors are excluded from the construction. As a consequence, we obtain convenient representation for the multi-particle form factors, establish recurrence relations between them and study their properties. The proposed construction is used to obtain the free-field representation of the lightest particles form factors in the Φ1,2\Phi_{1,2} perturbed minimal models. As a significant example we consider the Ising model in a magnetic field. We check that the results obtained in the framework of the proposed free-field representation are in agreement with the corresponding results obtained by solving the bootstrap equations.Comment: 20 pages; v2: some misprints, textual inaccuracies and references corrected; some references and remarks adde
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