14,802 research outputs found
Meta-Stable Brane Configurations by Higher Order Polynomial Superpotential
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
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
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
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
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
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
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 CrFeO ({}=La, Sr
The nearly well-ordered double perovskite LaCrFeO has been
synthesized recently. Contrary to previous theoretical predictions, but in
agreement with experimental observations, our first principle calculations
indicate an insulating ferrimagnet LaCrFeO with antialigned S=3/2
Cr and S=5/2 Fe 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
SrCrFeO, which is as yet unsynthesized. In LSDA calculations, this
system shows formally tetravalent Cr and Fe ions both having antialigned =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 SrCrFeO.Comment: 7 page
Titania/alumina bilayer gate insulators for InGaAs metal-oxide-semiconductor devices
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
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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