Higher Derivative Terms in the Effective Action of N=2 SUSY QCD from Instantons

We consider N=2 SUSY QCD with gauge group SU(2) and N_f flavours of matter with nonzero mass. Using the method of the instanton-induced effective vertex we calculate higher derivative corrections to the Seiberg-Witten result in the momentum expansion of the low energy effective Lagrangian in various regions of the modular space. Then we focus on a certain higher derivative operator on the Higgs branch. We show that the singular behavior of this operator comes from values of mass of matter at which charge singularity on the Coulomb branch collides with the monopole or dyon one. Given the behavior of this operator at weak coupling coming from instantons as well as its behavior near points of colliding singularities we find the exact solution for this operator.Comment: 33 pages, LATEX file. Final version to appear in Nuclear Physics B. Misprints corrected, exact solution in section 5 is slightly modifie

Derived length and nilpotency class of zero entropy groups acting on compact Kahler manifolds

Let X be a compact Kahler manifold of dimension n and of Kodaira dimension kappa(X). Let G be a group of zero entropy automorphisms of X and G_0 the set of elements in G which are isotopic to the identity. We prove that replacing G by a suitable finite-index subgroup, G/G_0 is a unipotent group of derived length at most n-max(kappa(X),1) and the derived length of G is at most n-kappa(X). Up to taking a finite-index subgroup, we conjecture that the nilpotency class c(G/G_0) of G/G_0 is at most n-1. The conjecture is proved to be true for all complex tori. Assuming this conjecture for all compact Kahler manifolds, we show that c(G) is at most n-kappa(X). The algebro-geometric structure of X is studied when c(G)=n or c(G/G_0)=n-1. We also give an optimal upper bound of the size of the Jordan blocks of the unipotent automorphisms of H^2(X,C) induced by automorphisms of X.Comment: New version joined with Hsueh-Yung LIN. 38 pages. New results have been added and a mistake was fixe

In situ observations on deformation behavior and stretching-induced failure of fine pitch stretchable interconnect

Electronic devices capable of performing in extreme mechanical conditions such as stretching, bending, or twisting will improve biomedical and wearable systems. The required capabilities cannot be achieved with conventional building geometries, because of structural rigidity and lack of mechanical stretchability. In this article, a zigzag-patterned structure representing a stretchable interconnect is presented as a promising type of building block. In situ experimental observations on the deformed interconnect are correlated with numerical analysis, providing an understanding of the deformation and failure mechanisms. The experimental results demonstrate that the zigzag-patterned interconnect enables stretchability up to 60% without rupture. This stretchability is accommodated by in-plane rotation of arms and out-of-plane deformation of crests. Numerical analysis shows that the dominating failure cause is interfacial in-plane shear stress. The plastic strain concentration at the arms close to the crests, obtained by numerical simulation, agrees well with the failure location observed in the experiment

Integrable O(n) model on the honeycomb lattice via reflection matrices : Surface critical behaviour

We study the $O(n)$ loop model on the honeycomb lattice with open boundary conditions. Reflection matrices for the underlying Izergin-Korepin $R$-matrix lead to three inequivalent sets of integrable boundary weights. One set, which has previously been considered, gives rise to the ordinary surface transition. The other two sets correspond respectively to the special surface transition and the mixed ordinary-special transition. We analyse the Bethe ansatz equations derived for these integrable cases and obtain the surface energies together with the central charges and scaling dimensions characterizing the corresponding phase transitions.Comment: LaTeX, 29 pages, with 5 PostScript figure

Search for quantum dimer phases and transitions in a frustrated spin ladder

A two-leg spin-1/2 ladder with diagonal interactions is investigated numerically. We focus our attention on the possibility of columnar dimer phase, which was recently predicted based on a reformulated bosonization theory. By using density matrix renormalization group technique and exact diagonalization method, we calculate columnar dimer order parameter, spin correlation on a rung, string order parameters, and scaled excitation gaps. Carefully using various finite-size scaling techniques, our results show no support for the existence of columnar dimer phase in the spin ladder under consideration.Comment: 5 pages, 4 figures. To be published in Phys. Rev.

Type I Superconductivity upon Monopole Condensation in Seiberg-Witten Theory

We study the confinement scenario in N=2 supersymmetric SU(2) gauge theory near the monopole point upon breaking of N=2 supersymmetry by the adjoint matter mass term. We confirm claims made previously that the Abrikosov-Nielsen-Olesen string near the monopole point fails to be a BPS state once next-to-leading corrections in the adjoint mass parameter taken into account. Our results shows that type I superconductivity arises upon monopole condensation. This conclusion allows us to make qualitative predictions on the structure of the hadron mass spectrum near the monopole point.Comment: LaTex, 25 pages. Minor changes. To be published in NP

On the Formation of Peer-to-Peer Networks: Self-Organized Sharing and Groups

In this paper, we investigate the formation of peer-to-peer (P2P) networks with rational participating agents (active peers). In the absence of a central planner, peers choose their own utility-maximizing strategies for coalition and peer formation. P2P networks evolve dynamically through the activities of interactions among individual nodes and group units. We propose a framework for multilevel formation dynamics, including an individual level (content sharing decision and group selection) and a group level (membership admission). The respective utilities of the individual node and the collective player are formulated as functions of operational performance metrics such as expected content availability, search delay, transmission delay, and download delay. We study the impacts of various system parameters on the emergence of self-organized P2P network configuration features such as free-riding level and group size. Furthermore, we investigate the stability and efficiency of P2P networks and propose internal transfer mechanisms that force stable networks to become efficient

Atmospheric Chemistry of Venus-like Exoplanets

We use thermodynamic calculations to model atmospheric chemistry on terrestrial exoplanets that are hot enough for chemical equilibira between the atmosphere and lithosphere, as on Venus. The results of our calculations place constraints on abundances of spectroscopically observable gases, the surface temperature and pressure, and the mineralogy of the surface. These results will be useful in planning future observations of the atmospheres of terrestrial-sized exoplanets by current and proposed space observatories such as the Hubble Space Telescope (HST), Spitzer, James Webb Space Telescope (JWST), Terrestrial Planet Finder, and Darwin.Comment: 35 pages, 4 figures, 3 tables; 1 appendix; submitted to ApJ; version

Cloning transformations in spin networks without external control

In this paper we present an approach to quantum cloning with unmodulated spin networks. The cloner is realized by a proper design of the network and a choice of the coupling between the qubits. We show that in the case of phase covariant cloner the XY coupling gives the best results. In the 1->2 cloning we find that the value for the fidelity of the optimal cloner is achieved, and values comparable to the optimal ones in the general N->M case can be attained. If a suitable set of network symmetries are satisfied, the output fidelity of the clones does not depend on the specific choice of the graph. We show that spin network cloning is robust against the presence of static imperfections. Moreover, in the presence of noise, it outperforms the conventional approach. In this case the fidelity exceeds the corresponding value obtained by quantum gates even for a very small amount of noise. Furthermore we show how to use this method to clone qutrits and qudits. By means of the Heisenberg coupling it is also possible to implement the universal cloner although in this case the fidelity is 10% off that of the optimal cloner.Comment: 12 pages, 13 figures, published versio

Exact solution for the spin-ss XXZ quantum chain with non-diagonal twists

We study integrable vertex models and quantum spin chains with toroidal boundary conditions. An interesting class of such boundaries is associated with non-diagonal twist matrices. For such models there are no trivial reference states upon which a Bethe ansatz calculation can be constructed, in contrast to the well-known case of periodic boundary conditions. In this paper we show how the transfer matrix eigenvalue expression for the spin-$s$ XXZ chain twisted by the charge-conjugation matrix can in fact be obtained. The technique used is the generalization to spin-$s$ of the functional relation method based on ``pair-propagation through a vertex''. The Bethe ansatz-type equations obtained reduce, in the case of lattice size $N=1$, to those recently found for the Hofstadter problem of Bloch electrons on a square lattice in a magnetic field.Comment: 25 pages, LaTe