Gaugino Condensation and Nonperturbative Superpotentials in Flux Compactifications

There are two known sources of nonperturbative superpotentials for K\"ahler moduli in type IIB orientifolds, or F-theory compactifications on Calabi-Yau fourfolds, with flux: Euclidean brane instantons and low-energy dynamics in D7 brane gauge theories. The first class of effects, Euclidean D3 branes which lift in M-theory to M5 branes wrapping divisors of arithmetic genus 1 in the fourfold, is relatively well understood. The second class has been less explored. In this paper, we consider the explicit example of F-theory on $K3 \times K3$ with flux. The fluxes lift the D7 brane matter fields, and stabilize stacks of D7 branes at loci of enhanced gauge symmetry. The resulting theories exhibit gaugino condensation, and generate a nonperturbative superpotential for K\"ahler moduli. We describe how the relevant geometries in general contain cycles of arithmetic genus $\chi \geq 1$ (and how $\chi > 1$ divisors can contribute to the superpotential, in the presence of flux). This second class of effects is likely to be important in finding even larger classes of models where the KKLT mechanism of moduli stabilization can be realized. We also address various claims about the situation for IIB models with a single K\"ahler modulus.Comment: 24 pages, harvmac, no figures, references adde

Third order Bose-Einstein correlations by means of Coulomb wave function revisited

In previous works, in order to include correction by the Coulomb wave function in Bose-Einstein correlations (BEC), the two-body Coulomb scattering wave functions have been utilized in the formulation of three-body BEC. However, the three-body Coulomb scattering wave function, which satisfies approximately the three-body Coulomb scattering Schrodinger equation, cannot be written by the product of the two-body scattering wave functions. Therefore, we reformulate the three-body BEC, and reanalyze the data. A set of reasonable parameters is obtained.Comment: 9 pages, 5 figure

Orbital motions as gradiometers for post-Newtonian tidal effects

The direct long-term changes occurring in the orbital dynamics of a local gravitationally bound binary system $S$ due to the post-Newtonian tidal acceleration caused by an external massive source are investigated. A class of systems made of a test particle $m$ rapidly orbiting with orbital frequency $n_{\rm b}$ an astronomical body of mass $M$ which, in turn, slowly revolves around a distant object of mass $M^{'}$ with orbital frequency $n_{\rm b}^{'}\ll n_{\rm b}$ is considered. The characteristic frequencies of the non-Keplerian orbital variations of $m$ and of $M$ itself are assumed to be negligible with respect to both $n_{\rm b}$ and $n_{\rm b}^{'}$. General expressions for the resulting Newtonian and post-Newtonian tidal orbital shifts of $m$ are obtained. The future missions BepiColombo and JUICE to Mercury and Ganymede, respectively, are considered in view of a possible detection. The largest effects, of the order of $\approx 0.1-0.5$ milliarcseconds per year (mas yr$^{-1}$), occur for the Ganymede orbiter of the JUICE mission. Although future improvements in spacecraft tracking and orbit determination might, perhaps, reach the required sensitivity, the systematic bias represented by the other known orbital perturbations of both Newtonian and post-Newtonian origin would be overwhelming. The realization of a dedicated artificial mini-planetary system to be carried onboard and Earth-orbiting spacecraft is considered as well. Post-Newtonian tidal precessions as large as $\approx 1-10^2$ mas yr$^{-1}$ could be obtained, but the quite larger Newtonian tidal effects would be a major source of systematic bias because of the present-day percent uncertainty in the product of the Earth's mass times the Newtonian gravitational parameter.Comment: LaTex2e, 20 pages, no figures, 3 tables. Accepted for publication in Frontiers in Astronomy and Space Sciences - Cosmolog

A comparison of the Caulobacter NA1000 and K31 genomes reveals extensive genome rearrangements and differences in metabolic potential

The genus Caulobacter is found in a variety of habitats and is known for its abilityto thrive in low-nutrient conditions. K31 is a novel Caulobacter isolate that has the ability to tolerate copper and chlorophenols, and can grow at 48Cwith a doubling time of 40 h. K31 contains a 5.5 Mb chromosome that codes for more than 5500 proteins and two large plasmids (234 and 178 kb) thatcode for 438 additional proteins. A comparison of the K31 and the Caulobactercrescentus NA1000 genomes revealed extensive rearrangements of gene order,suggesting that the genomes had been randomly scrambled. However, a careful analysis revealed that the distance from the origin of replication was conserved for the majority of the genes and that many of the rearrangements involved inversions that included the origin of replication. On a finer scale, numerous small indels were observed. K31 proteins involved in essential functions shared 80-95% amino acid sequence identity with their C. crescentus homologues,while other homologue pairs tended to have lower levels of identity.In addition, the K31 chromosome contains more than 1600 genes with nohomologue in NA1000

Reflection K-Matrices for 19-Vertex Models

We derive and classify all regular solutions of the boundary Yang-Baxter equation for 19-vertex models known as Zamolodchikov-Fateev or $A_{1}^{(1)}$ model, Izergin-Korepin or $A_{2}^{(2)}$ model, sl(2|1) model and osp(2|1) model. We find that there is a general solution for $A_{1}^{(1)}$ and sl(2|1) models. In both models it is a complete K-matrix with three free parameters. For the $A_{2}^{(2)}$ and osp(2|1) models we find three general solutions, being two complete reflection K-matrices solutions and one incomplete reflection K-matrix solution with some null entries. In both models these solutions have two free parameters. Integrable spin-1 Hamiltonians with general boundary interactions are also presented. Several reduced solutions from these general solutions are presented in the appendices.Comment: 35 pages, LaTe

Nonlocal Coupled HI-MKdV Systems

We first study coupled Hirota-Iwao modified KdV (HI-mKdV) systems and give all possible local and nonlocal reductions of these systems. We then present Hirota bilinear forms of these systems and give one-soliton solutions of them with the help of pfaffians. By using the soliton solutions of the coupled HI-mKdV systems for $N=2,3,$ and $N=4$ we find one-soliton solutions of the local and nonlocal reduced equations.Comment: 32 pages, 14 figure