409 research outputs found

    Modularity and 4D-2D spectral equivalences for large-N gauge theories with adjoint matter

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    In recent work, we demonstrated that the confined-phase spectrum of non-supersymmetric pure Yang-Mills theory coincides with the spectrum of the chiral sector of a two-dimensional conformal field theory in the large-NN limit. This was done within the tractable setting in which the gauge theory is compactified on a three-sphere whose radius is small compared to the strong length scale. In this paper, we generalize these observations by demonstrating that similar results continue to hold even when massless adjoint matter fields are introduced. These results hold for both thermal and (1)F(-1)^F-twisted partition functions, and collectively suggest that the spectra of large-NN confining gauge theories are organized by the symmetries of two-dimensional conformal field theories.Comment: 51 pages, LaTeX, 3 figure

    Hurdle Rates and High-Watermarks: Incentives or Restrictions?

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    We analyze how hedge fund attributes affect performance and the decision to offer a hurdle rate and high-watermark. Our results indicate that hurdle rate and high-watermark act as restrictions on fee collection rather than incentives. Hedge funds that take riskier positions are more likely to offer a hurdle rate and high watermark. Controlling for fund size, our results also suggest that hedge funds that collect high performance fees are more likely to outperform those that collect low performance fees. Using three different measures of hedge fund performance in our cross sectional analysis and taking into account the risk profiles associated with different investment strategies, we confirm our results

    Holographic Pomeron and the Schwinger Mechanism

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    We revisit the problem of dipole-dipole scattering via exchanges of soft Pomerons in the context of holographic QCD. We show that a single closed string exchange contribution to the eikonalized dipole-dipole scattering amplitude yields a Regge behavior of the elastic amplitude; the corresponding slope and intercept are different from previous results obtained by a variational analysis of semi-classical surfaces. We provide a physical interpretation of the semi-classical worldsheets driving the Regge behavior for (-t)>0 in terms of worldsheet instantons. The latter describe the Schwinger mechanism for string pair creation by an electric field, where the longitudinal electric field E_L=\sigma_T tanh(\chi/2) at the origin of this non-perturbative mechanism is induced by the relative rapidity {\chi} of the scattering dipoles. Our analysis naturally explains the diffusion in the impact parameter space encoded in the Pomeron exchange; in our picture, it is due to the Unruh temperature of accelerated strings under the electric field. We also argue for the existence of a "micro-fireball" in the middle of the transverse space due to the soft Pomeron exchange, which may be at the origin of the thermal character of multiparticle production in ep/pp collisions. After summing over uncorrelated multi-Pomeron exchanges, we find that the total dipole-dipole cross section obeys the Froissart unitarity bound.Comment: 17 pages, 4 figures, version 2: minor typos corrected, references adde

    The use of sesame oil in sea bream feeds and its effects on growth and body chemical composition

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    As fish oil availability declines worldwide and its price rises, there is a growing need to engage in scientific investigations into alternative oil sources for incorporation into fish feeds. This study aimed to determine the effects of dietary sesame oil on the growth performance, feed utilization, and nutritional composition of sea bream (*Sparus aurata*). Twenty-five individual fish (initial mean weight: 32.38±0.27 g) were placed in each tank in triplicate. Four experimental fish meal-based (iso-proteic 49% and iso-lipidic 20%) diets were formulated; the control (C) group contains 100% of fish oil (FO) and varying amounts (20, 40, 60%) of sesame oil (SO). During the 75-day experiment, the fish were fed 3 times a day, and the mean ambient temperature and dissolved oxygen values were measured as 22.5±0.5°C and 6.8±0.3 mg/L, respectively. At the beginning of the experiment, 20 fish were sampled to determine their nutrient composition and somatic indexes. In the end, 4 fish were collected for the same procedures and 4 for each tank's muscle and liver fatty acid compositions. At the end of the study, the S60 group exhibited the lowest final weight (FW) and feed utilization parameters. On the other hand, there were no statistical differences between FO, SO20, and SO40 in terms of FW. In addition, the SO40 group had the best feed conversion ratio (FCR) among the groups (P\<0.05). The whole-body lipid compositions of the groups were different. The highest lipid level was found in SO40 with 15.83±0.36%. Muscle and liver fatty acid composition was significantly affected by the fatty acid profile of experimental feeds. While total ω-6 fatty acids were higher in the SO groups than in group C, total ω-3 fatty acids were higher in the C group compared to the SO groups (P\<0.05). The ω-3/ω-6 ratios in the SO20 and SO40 groups showed similarity, while the highest ratio was observed in the control group (P\<0.05). As a result, according to data obtained from our study, it is predicted that 40% SO could be added to sea bream feed instead of FO in terms of growth performance, feed utilization, and nutritional composition

    Effect of photoperiod and host distribution on the horizontal transmission of Isaria fumosorosea (Hypocreales: Cordycipitaceae) in greenhouse whitefly assessed using a novel model bioassay

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    A model bioassay was used to evaluate the epizootic potential and determine the horizontal transmission efficiency of Isaria fumosorosea Trinidadian strains against Trialeurodes vaporariorum pharate adults under optimum conditions (25±0.5°C, ~100% RH) at two different photoperiods. Untreated pharate adults were arranged on laminated graph paper at different distributions to simulate varying infestation levels on a leaf surface. Four potential hosts were located 7, 14 and 21 mm away from a central sporulating cadaver simulating high, medium and low infestation levels, respectively. Percent hosts colonized were recorded 7, 12, 14 and 21 days post-treatment during a 16- and 24-h photophase. After 21 days, mean percent hosts colonized at the highest, middle and lowest infestation levels were 93 and 100%, 22 and 58%, 25 and 39% under a 16- and 24-h photophase, respectively. From the results, it was concluded that the longer the photophase, the greater the percentage of hosts colonized, and as host distance increased from the central sporulating cadaver, colonization decreased. The use of this novel model bioassay technique is the first attempt to evaluate the epizootic potential and determine the horizontal transmission efficiency of I. fumosorosea Trinidadian strains under optimal environmental conditions at different photoperiods. This bioassay can be used to assess horizontal transmission efficiency for the selection of fungi being considered for commercial biopesticide development

    A Gauge-Gravity Relation in the One-loop Effective Action

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    We identify an unusual new gauge-gravity relation: the one-loop effective action for a massive spinor in 2n dimensional AdS space is expressed in terms of precisely the same function [a certain multiple gamma function] as the one-loop effective action for a massive charged scalar in 4n dimensions in a maximally symmetric background electromagnetic field [one for which the eigenvalues of F_{\mu\nu} are maximally degenerate, corresponding in 4 dimensions to a self-dual field, equivalently to a field of definite helicity], subject to the identification F^2 \Lambda, where \Lambda is the gravitational curvature. Since these effective actions generate the low energy limit of all one-loop multi-leg graviton or gauge amplitudes, this implies a nontrivial gauge-gravity relation at the non-perturbative level and at the amplitude level.Comment: 6 page

    Self-consistent crystalline condensate in chiral Gross-Neveu and Bogoliubov-de Gennes systems

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    We derive a new exact self-consistent crystalline condensate in the 1+1 dimensional chiral Gross-Neveu model. This also yields a new exact crystalline solution for the one dimensional Bogoliubov-de Gennes equations and the Eilenberger equation of semiclassical superconductivity. We show that the functional gap equation can be reduced to a solvable nonlinear equation, and discuss implications for the temperature-chemical potential phase diagram.Comment: 5 pages, 5 figures; v2 minor corrections, version for PR

    Gross-Neveu Models, Nonlinear Dirac Equations, Surfaces and Strings

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    Recent studies of the thermodynamic phase diagrams of the Gross-Neveu model (GN2), and its chiral cousin, the NJL2 model, have shown that there are phases with inhomogeneous crystalline condensates. These (static) condensates can be found analytically because the relevant Hartree-Fock and gap equations can be reduced to the nonlinear Schr\"odinger equation, whose deformations are governed by the mKdV and AKNS integrable hierarchies, respectively. Recently, Thies et al have shown that time-dependent Hartree-Fock solutions describing baryon scattering in the massless GN2 model satisfy the Sinh-Gordon equation, and can be mapped directly to classical string solutions in AdS3. Here we propose a geometric perspective for this result, based on the generalized Weierstrass spinor representation for the embedding of 2d surfaces into 3d spaces, which explains why these well-known integrable systems underlie these various Gross-Neveu gap equations, and why there should be a connection to classical string theory solutions. This geometric viewpoint may be useful for higher dimensional models, where the relevant integrable hierarchies include the Davey-Stewartson and Novikov-Veselov systems.Comment: 27 pages, 1 figur

    Inhomogeneous Condensates in the Thermodynamics of the Chiral NJL_2 model

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    We analyze the thermodynamical properties, at finite density and nonzero temperature, of the (1+1)-dimensional chiral Gross-Neveu model (the NJL_2 model), using the exact inhomogeneous (crystalline) condensate solutions to the gap equation. The continuous chiral symmetry of the model plays a crucial role, and the thermodynamics leads to a broken phase with a periodic spiral condensate, the "chiral spiral", as a thermodynamically preferred limit of the more general "twisted kink crystal" solution of the gap equation. This situation should be contrasted with the Gross-Neveu model, which has a discrete chiral symmetry, and for which the phase diagram has a crystalline phase with a periodic kink crystal. We use a combination of analytic, numerical and Ginzburg-Landau techniques to study various parts of the phase diagram.Comment: 28 pages, 13 figure
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