9,059 research outputs found
Exact partition function in ABJM theory deformed by mass and Fayet-Iliopoulos terms
We exactly compute the partition function for ABJM
theory on deformed by mass and Fayet-Iliopoulos parameter
. For , the partition function has an infinite number of
Lee-Yang zeros. For general , in the decompactification limit the theory
exhibits a quantum (first-order) phase transition at .Comment: 11 pages, 1 figure. v2: references adde
Catalogue of the ectoparasitic insects of the bats of Argentina
Taxonomy and distribution of the ectoparasitic insects of bats from Argentina, are reviewed. Seventeen species of Diptera (six of Nycteribiidae and eleven of Streblidae), six species of Siphonaptera (four ofIschnopsyllidae, one of Pulicidae, and one ofStephanocircidae), and seven species of Hemiptera (Polyctenidae) are known presently for Argentina. The information was obtained by reviewing the literature and collecting in the field between 1989 and 1998. The specimens collected in the field were compared with the type material
deposited at the Field Museum of Natural History (CHNM).En este primer catalogo de insectos ectoparasitos de murcielagos de la Argentina, se ofrece informacion sobre taxonomia y distribucion. Se conocen actualmente en el pais 17 especies de Diptera (seis de Nycteribiidae yonce de Streblidae), seis de Siphonaptera (cuatro de Ischnopsyllidae, una de Pulicidae y una de Stephanocircidae) y siete especies de Hemiptera (Polyctenidae). Se consulto numerosa literatura sobre los distintos grupos y se reviso abundante material obtenido en viajes de campana realizados desde 1989 a 1998, a numerosas localidades de la Argentina. Se realizaron comparaciones con material tipo del Field Museum of Natural History (CHNM)
Spectrum of three-body bound states in a finite volume
The spectrum of a bound state of three identical particles with a mass in
a finite cubic box is studied. It is shown that in the unitary limit, the
energy shift of a shallow bound state is given by , where
is the bound-state momentum, is the box size, denotes the
three-body analog of the asymptotic normalization coefficient of the bound
state wave function and is a numerical constant. The formula is valid for
.Comment: An error in the calculation of the overlap integral in Eq. (11) is
corrected. Our main result given in Eq. (26) remains the same, except the
numerical value of the constant c, which changes approximately by 10
Associative memory on a small-world neural network
We study a model of associative memory based on a neural network with
small-world structure. The efficacy of the network to retrieve one of the
stored patterns exhibits a phase transition at a finite value of the disorder.
The more ordered networks are unable to recover the patterns, and are always
attracted to mixture states. Besides, for a range of the number of stored
patterns, the efficacy has a maximum at an intermediate value of the disorder.
We also give a statistical characterization of the attractors for all values of
the disorder of the network.Comment: 5 pages, 4 figures (eps
Regional Contagion and the Globalization of Securities Markets
This paper argues that the globalization of securities markets may promote contagion among investors by weakening incentives for gathering costly country-specific information and by strengthening incentives for imitating arbitrary market portfolios. In the presence of short-selling constraints, the utility gain of gathering information at a fixed cost converges to a constant level and may diminish as securities markets grow. Moreover, if a portfolio manager's marginal cost for yielding below-market returns exceeds the marginal gain for above-market returns, there is a range of optimal portfolios in which all investors imitate arbitrary market portfolios and this range widens as the market grows. Numerical simulations suggest that these frictions can have significant quantitative implications and they may induce large capital flows in emerging markets.
Supersymmetric Chern-Simons-matter theory and phase transitions
We study supersymmetric Chern-Simons with
fundamental and antifundamental chiral multiplets of mass in the
complete parameter space spanned by , where denotes
the coupling constant. In particular, we analyze the matrix model description
of its partition function, both at finite using the method of orthogonal
polynomials together with Mordell integrals and, at large with fixed ,
using the theory of Toeplitz determinants. We show for the massless case that
there is an explicit realization of the Giveon-Kutasov duality. For finite ,
with , three regimes that exactly correspond to the known three large
phases of theory are identified and characterized.Comment: 28 pages, v3: Minor modification to match published versio
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