Vacua of N=1 Supersymmetric QCD from Spin Chains and Matrix Models

We consider the vacuum structure of the finite N=2 theory with N_f=2N fundamental hypermultiplets broken to N=1 by a superpotential for the adjoint chiral multiplet. We do this in two ways: firstly, by compactification to three dimensions, in which case the effective superpotential is the Hamiltonian of an integrable spin chain. In the second approach, we consider the Dijkgraaf-Vafa holomorphic matrix model. We prove that the two approaches agree as long as the couplings of the two theories are related in a particular way involving an infinite series of instanton terms. The case of gauge group SU(2) with N_f=4 is considered in greater detail.Comment: 28 pages, 2 figure

Systematic perturbation approach for a dynamical scaling law in a kinetically constrained spin model

The dynamical behaviours of a kinetically constrained spin model (Fredrickson-Andersen model) on a Bethe lattice are investigated by a perturbation analysis that provides exact final states above the nonergodic transition point. It is observed that the time-dependent solutions of the derived dynamical systems obtained by the perturbation analysis become systematically closer to the results obtained by Monte Carlo simulations as the order of a perturbation series is increased. This systematic perturbation analysis also clarifies the existence of a dynamical scaling law, which provides a implication for a universal relation between a size scale and a time scale near the nonergodic transition.Comment: 17 pages, 7 figures, v2; results have been refined, v3; A figure has been modified, v4; results have been more refine

Exactly soluble model for self-gravitating D-particles with the wormhole

We consider D-particles coupled to the CGHS dilaton gravity and obtain the exact wormhole geometry and trajectories of D-particles by introducing the exotic matter. The initial static wormhole background is not stable after infalling D-particles due to the classical backreaction of the geometry so that the additional exotic matter source should be introduced for the stability. Then, the traversable wormhole geometry naturally appears and the D-particles can travel through it safely. Finally, we discuss the dynamical evolution of the wormhole throat and the massless limit of D-particles.Comment: 16 pages, 3 figures, revte

Supersymmetric D-brane Bound States with B-field and Higher Dimensional Instantons on Noncommutative Geometry

We classify supersymmetric D0-Dp bound states with a non-zero B-field by considering T-dualities of intersecting branes at angles. Especially, we find that the D0-D8 system with the B-field preserves 1/16, 1/8 and 3/16 of supercharges if the B-field satisfies the ``(anti-)self-dual'' condition in dimension eight. The D0-branes in this system are described by eight dimensional instantons on non-commutative R^8. We also discuss the extended ADHM construction of the eight-dimensional instantons and its deformation by the B-field. The modified ADHM equations admit a sort of the `fuzzy sphere' (embeddings of SU(2)) solution.Comment: 20 pages, LaTeX file, typos corrected and references adde

New Resources and Perspectives for Biomedical Event Extraction

Event extraction is a major focus of recent work in biomedical information extraction. Despite substantial advances, many challenges still remain for reliable automatic extraction of events from text. We introduce a new biomedical event extraction resource consisting of analyses automatically created by systems participating in the recent BioNLP Shared Task (ST) 2011. In providing for the first time the outputs of a broad set of state-ofthe-art event extraction systems, this resource opens many new opportunities for studying aspects of event extraction, from the identification of common errors to the study of effective approaches to combining the strengths of systems. We demonstrate these opportunities through a multi-system analysis on three BioNLP ST 2011 main tasks, focusing on events that none of the systems can successfully extract. We further argue for new perspectives to the performance evaluation of domain event extraction systems, considering a document-level, “off-the-page ” representation and evaluation to complement the mentionlevel evaluations pursued in most recent work.

Dynamical p-branes with a cosmological constant

We present a class of dynamical solutions in a D-dimensional gravitational theory coupled to a dilaton, a form field strength, and a cosmological constant. We find that for any D due to the presence of a cosmological constant, the metric of solutions depends on a quadratic function of the brane world volume coordinates, and the transverse space cannot be Ricci flat except for the case of 1-branes. We then discuss the dynamics of 1-branes in a D-dimensional spacetime. For a positive cosmological constant, 1-brane solutions with D>4 approach the Milne universe in the far-brane region. On the other hand, for a negative cosmological constant, each 1-brane approaches the others as the time evolves from a positive value, but no brane collision occurs for D>4, since the spacetime close to the 1-branes eventually splits into the separate domains. In contrast, the D=3 case provides an example of colliding 1-branes. Finally, we discuss the dynamics of 0-branes and show that for D>2, they behave like the Milne universe after the infinite cosmic time has passed.Comment: 21 pages, 7 figures; v2: minor correction