14,802 research outputs found

    Meta-Stable Brane Configurations by Higher Order Polynomial Superpotential

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    We construct the type IIA nonsupersymmetric meta-stable brane configuration consisting of (2k+1) NS5-branes and D4-branes where the electric gauge theory superpotential has an order (2k+2) polynomial for the bifundamentals. We find a rich pattern of nonsupersymmetric meta-stable states as well as the supersymmetric stable ones. By adding the orientifold 4-plane to this brane configuration, we also describe the intersecting brane configuration of type IIA string theory corresponding to the meta-stable nonsupersymmetric vacua of corresponding gauge theory.Comment: 27pp, 8 figures; some footnotes added; to appear in IJMP

    The Gauge Dual of Gauged N=8 Supergravity Theory

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    The most general SU(3)-singlet space of gauged N=8 supergravity in four-dimensions is studied recently. The SU(3)-invariant six scalar fields are realized by six real four-forms. A family of holographic N=1 supersymmetric RG flows on M2-branes in three-dimensions is described. This family of flows is driven by three independent mass parameters from the N=8 SO(8) theory and is controlled by two IR fixed points, N=1 G_2-invariant one and N=2 SU(3) x U(1)-invariant one. The generic flow with arbitrary mass parameters is N=1 supersymmetric and reaches to the N=2 SU(3) x U(1) fixed point where the three masses become identical. A particular N=1 supersymmetric SU(3)-preserving RG flow from the N=1 G_2-invariant fixed point to the N=2 SU(3) x U(1)-invariant fixed point is also discussed.Comment: 19pp; added the footnote 1, improved the conclusion and to appear in IJMP

    OPE in planar QCD from integrability

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    We consider the operator product expansion of local single-trace operators composed of the self-dual components of the field strength tensor in planar QCD. Using the integrability of the one-loop matrix of anomalous dimensions of such operators, we obtain a determinant expression for certain tree-level structure constants in the OPE.Comment: 20 pages, 5 figures; v2: added refs and discussion of general structure constant

    The QCD spin chain S matrix

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    Beisert et al. have identified an integrable SU(2,2) quantum spin chain which gives the one-loop anomalous dimensions of certain operators in large N QCD. We derive a set of nonlinear integral equations (NLIEs) for this model, and compute the scattering matrix of the various (in particular, magnon) excitations.Comment: 25 pages, 1 figure; v2: references adde

    Perturbing Around A Warped Product Of AdS_4 and Seven-Ellipsoid

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    We compute the spin-2 Kaluza-Klein modes around a warped product of AdS_4 and a seven-ellipsoid. This background with global G_2 symmetry is related to a U(N) x U(N) N=1 superconformal Chern-Simons matter theory with sixth order superpotential. The mass-squared in AdS_4 is quadratic in G_2 quantum number and KK excitation number. We determine the dimensions of spin-2 operators using the AdS/CFT correspondence. The connection to N=2 theory preserving SU(3) x U(1)_R is also discussed.Comment: 21pp; The second and last paragraphs of section 2, the footnotes 1 and 2 added and to appear in JHE

    Meta-Stable Brane Configurations by Adding an Orientifold-Plane to Giveon-Kutasov

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    In hep-th/0703135, they have found the type IIA intersecting brane configuration where there exist three NS5-branes, D4-branes and anti-D4-branes. By analyzing the gravitational interaction for the D4-branes in the background of the NS5-branes, the phase structures in different regions of the parameter space were studied in the context of classical string theory. In this paper, by adding the orientifold 4-plane and 6-plane to the above brane configuration, we describe the intersecting brane configurations of type IIA string theory corresponding to the meta-stable nonsupersymmetric vacua of these gauge theories.Comment: 21 pp, 6 figures; reduced bytes of figures, DBI action analysis added and to appear in JHE

    The boundary supersymmetric sine-Gordon model revisited

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    We argue that, contrary to previous claims, the supersymmetric sine-Gordon model with boundary has a two-parameter family of boundary interactions which preserves both integrability and supersymmetry. We also propose the corresponding boundary S matrix for the first supermultiplet of breathers.Comment: 9 pages, LaTeX; amssymb, no figures; v2: one equation and one reference added; v3: more references and a "note added

    Evaluation of Half-metallic Antiferromagnetism in A2{\cal A}_2CrFeO6_6 ({A\cal A}=La, Sr

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    The nearly well-ordered double perovskite La2_2CrFeO6_6 has been synthesized recently. Contrary to previous theoretical predictions, but in agreement with experimental observations, our first principle calculations indicate an insulating ferrimagnet La2_2CrFeO6_6 with antialigned S=3/2 Cr3+^{3+} and S=5/2 Fe3+^{3+} ions,using the local spin density approximation (LSDA), a correlated band theory LDA+U, and a semilocal functional modified Becke-Johnson method. Additionally, we investigated the double perovskite Sr2_2CrFeO6_6, which is as yet unsynthesized. In LSDA calculations, this system shows formally tetravalent Cr and Fe ions both having antialigned SS=1 moments, but is a simple metal. Once applying on-site Coulomb repulsion U on both Cr and Fe ions, this system becomes half-metallic and the moment of Fe is substantially reduced, resulting in zero net moment. These results are consistent with our fixed spin moment studies. Our results suggest a precisely compensated half-metallic Sr2_2CrFeO6_6.Comment: 7 page

    Titania/alumina bilayer gate insulators for InGaAs metal-oxide-semiconductor devices

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    We describe the electrical properties of atomic layer deposited TiO<sub>2</sub>/Al<sub>2</sub>O<sub>3</sub> bilayer gate oxides which simultaneously achieve high gate capacitance density and low gate leakage current density. Crystallization of the initially amorphous TiO<sub>2</sub> film contributes to a significant accumulation capacitance increase (∼33%) observed after a forming gas anneal at 400 °C. The bilayer dielectrics reduce gate leakage current density by approximately one order of magnitude at flatband compared to Al<sub>2</sub>O<sub>3</sub> single layer of comparable capacitance equivalent thickness. The conduction band offset of TiO<sub>2</sub> relative to InGaAs is 0.6 eV, contributing to the ability of the stacked dielectric to suppress gate leakage conduction

    NLIE for hole excited states in the sine-Gordon model with two boundaries

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    We derive a nonlinear integral equation (NLIE) for some bulk excited states of the sine-Gordon model on a finite interval with general integrable boundary interactions, including boundary terms proportional to the first time derivative of the field. We use this NLIE to compute numerically the dimensions of these states as a function of scale, and check the UV and IR limits analytically. We also find further support for the ground-state NLIE by comparison with boundary conformal perturbation theory (BCPT), boundary truncated conformal space approach (BTCSA) and the boundary analogue of the Luscher formula.Comment: 31 pages, LaTeX; graphicx, epstopdf, 4 figure
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