13806519
Gauge Theoretical Construction of Non-compact Calabi–Yau Manifolds
Abstract We construct the non-compact Calabi–Yau manifolds interpreted as the complex line bundles over the Hermitian symmetric spaces. These manifolds are the various generalizations of the complex line bundle over C P N −1 . Imposing an F-term constraint on the line bundle over C P N −1 , we obtain the line bundle over the complex quadric surface Q N −2 . On the other hand, when we promote the U (1) gauge symmetry in C P N −1 to the non-abelian gauge group U ( M ), the line bundle over the Grassmann manifold is obtained. We construct the non-compact Calabi–Yau manifolds with isometries of exceptional groups, which we have not discussed in the previous papers. Each of these manifolds contains the resolution parameter which controls the size of the base manifold, and the conical singularity appears when the parameter vanishes.
651290
A note on conifolds
Abstract We present the Ricci-flat metric and its Kahler potential on the conifold with the O ( N ) isometry, whose conical singularity is repaired by the complex quadric surface Q N −2 = SO ( N )/ SO ( N −2)× U (1).
15579141
Calabi-Yau manifolds of cohomogeneity one as complex line bundles
Abstract We present a simple derivation of the Ricci-flat Kahler metric and its Kahler potential on the canonical line bundle over arbitrary Kahler coset space equipped with the Kahler–Einstein metric.
16515698
AdS vacua, attractor mechanism and generalized geometries
We consider flux vacua attractor equations in type IIA string theory compactified on generalized geometries with orientifold projections. The four-dimensional = 1 superpotential in this compactification can be written as the sum of the Ramond-Ramond superpotential and a term described by (non)geometric flux charges. We exhibit a simple model in which supersymmetric AdS and Minkowski solutions are classified by means of discriminants of the two superpotentials. We further study various configurations without Ramond-Ramond flux charges. In this case we find supersymmetric AdS vacua both in the case of compactifications on generalized geometries with SU(3) × SU(3) structures and on manifolds with an SU(3)-structure without nongeometric flux charges. In the latter case, we have to introduce correction terms into the prepotential in order to realize consistent vacua.
119125755
Chiral Zero Modes on intersecting Heterotic 5-branes
We show that there exist two 27 and one of E6, net one chiral supermultiplet as zero modes localized on the intersecting 5-branes in the E8 × E8 heterotic string theory. A heterotic background is constructed by the standard embedding in the smeared solution, and the Dirac equation is solved explicitly on this background. It provides, after the compactification of some of the transverse dimensions, an interesting five-dimensional brane-world set-up in heterotic string theory.
118395821
Type IIA orientifolds and orbifolds on non-factorizable tori
Abstract We investigate type II orientifolds on non-factorizable torus with and without its oribifolding. We explicitly calculate the Ramond–Ramond tadpole from string one-loop amplitudes, and confirm that the consistent number of orientifold planes is directly derived from the Lefschetz fixed point theorem. We furthermore classify orientifolds on non-factorizable Z N × Z M orbifolds, and construct new supersymmetric type IIA orientifold models on them.
55474215
Phase structure of topological insulators by lattice strong-coupling expansion
The effect of the strong electron correlation on the topological phase structure of 2-dimensional (2D) and 3D topological insulators is investigated, in terms of lattice gauge theory. The effective model for noninteracting system is constructed similarly to the lattice fermions with the Wilson term, corresponding to the spin-orbit coupling. Introducing the electron-electron interaction as the coupling to the gauge field, we analyze the behavior of emergent orders by the strong coupling expansion methods. We show that there appears a new phase with the in-plane antiferromagnetic order in the 2D topological insulator, which is similar to the so-called "Aoki phase" in lattice QCD with Wilson fermions. In the 3D case, on the other hand, there does not appear such a new phase, and the electron correlation results in the shift of the phase boundary between the topological phase and the normal phase.
119294442
Towards Holographic Spintronics
We study transport phenomena of total angular momentum in holography, as a first step toward holographic understanding of spin transport phenomena. Spin current, which has both the local Lorentz index for spins and the space-time vector index for current, couples naturally to the bulk spin connection. Therefore the bulk spin connection becomes the source for the boundary spin current. This allows us to evaluate the spin current holographically, with a relation to the stress tensor and metric fluctuations in the bulk. We examine the spin transport coefficients and the thermal spin Hall conductivity in a simple holographic setup.
15996221
Aoki phases in the lattice Gross-Neveu model with flavored mass terms
We investigate the parity-broken phase structure for staggered and naive fermions in the Gross-Neveu model as a toy model of QCD. We consider a generalized staggered Gross-Neveu model including two types of four-point interactions. We use generalized mass terms to split the doublers for both staggered and naive fermions. The phase boundaries derived from the gap equations show that the mass splitting of tastes results in an Aoki phase both in the staggered and naive cases. We also discuss the continuum limit of these models and explore taking the chirally symmetric limit by fine-tuning a mass parameter and two-coupling constants. This supports the idea that in lattice QCD we can derive one- or two-flavor staggered fermions by tuning the mass parameter, which are likely to be less expensive than Wilson fermions in QCD simulation.
119252242
Hofstadter problem in higher dimensions
We investigate some generalizations of the Hofstadter problem to higher dimensions with Abelian and non-Abelian gauge field configurations. We numerically show the hierarchical structure in the energy spectra with several lattice models. It is also pointed out the equivalence betwee the \pi-flux state and the staggered formalism of Dirac fermion.
118426022
The Chiral Heat Effect
(Received January 3, 2012; Revised May 1, 2012)We consider the thermal response of a (3+1)-dimensional theory with a chiral anomalyonacurved space motivatedbythechiralmagneticeﬀect. Weﬁnd anew phenomenon, calledthe chiral heat eﬀect, such that the thermal current is induced transverse to a gradient ofthe temperature even on a ﬂat space. We study a similar topological eﬀect on the spacetimewith a torsion.