arXiv subjects
Publications and source records attributed to Kenji Mohri.
We study the algebraic structure of the configuration space of the Kodaira-Spencer gravity theory on a Calabi-Yau threefold. We then investigate the deformation problem of the Kodaira-Spencer gravity at the classical level using the algebraic tools obtained here.
Motivated by the recent analysis of the E10 sigma model for the study of M theory, we study a one-dimensional sigma model associated with the hyperbolic Kac-Moody algebra G2H and its link to D=5, N=2 pure supergravity, which closely resembles in many ways D=11 supergravity. The bosonic equations of motion and the Bianchi identity for D=5 pure supergravity match the equations of the level l<=3 truncation of the G2H sigma model up to higher level terms, just as they do for the D=11 case. We also compute low level root and outer multiplicities in the A3 decomposition, and indeed find singlets at l=4k, k=2,3,... corresponding to the scaling of ER^{k+1} terms, although the missing singlet at l =4 remains a puzzle.
We investigate instanton expansions of partition functions of several toric E-string models using local mirror symmetry and elliptic modular forms. We also develop a method to obtain the Seiberg--Witten curve of E-string with arbitrary Wilson lines with the help of elliptic functions.
We revisit local mirror symmetry associated with del Pezzo surfaces in Calabi-Yau threefolds in view of five-dimensional N=1 E_N theories compactified on a circle. The mirror partner of singular Calabi-Yau with a shrinking del Pezzo four-cycle is described as the affine 7-brane backgrounds probed by a D3-brane. Evaluating the mirror map and the BPS central charge we relate junction charges to RR charges of D-branes wrapped on del Pezzo surfaces. This enables us to determine how the string junctions are mapped to D-branes on del Pezzo surfaces.
We study D-branes wrapping an exceptional four-cycle P(1,a,b) in a blown-up C^3/Z_m non-compact Calabi-Yau threefold with (m;a,b)=(3;1,1), (4;1,2) and (6;2,3). In applying the method of local mirror symmetry we find that the Picard-Fuchs equations for the local mirror periods in the Z_{3,4,6} orbifolds take the same form as the ones in the local E_{6,7,8} del Pezzo models, respectively. It is observed, however, that the orbifold models and the del Pezzo models possess different physical properties because the background NS B-field is turned on in the case of Z_{3,4,6} orbifolds. This is shown by analyzing the periods and their monodromies in full detail with the help of Meijer G-functions. We use the results to discuss D-brane configurations on P(1,a,b) as well as on del Pezzo surfaces. We also discuss the number theoretic aspect of local mirror symmetry and observe that the exponent which governs the exponential growth of the Gromov-Witten invariants is determined by the special value of the Dirichlet L-function.
We develop a method to analyze systematically the configuration space of a D-brane localized at the orbifold singular point of a Calabi--Yau $d$-fold of the form ${\Bbb C}^d/Γ$ using the theory of toric quotients. This approach elucidates the structure of the Kähler moduli space associated with the problem. As an application, we compute the toric data of the $Γ$-Hilbert scheme.
We investigate a (0,2) gauge theory realized on the world volume of the type IIB D1-brane at the singular point of a Calabi-Yau fourfold. It is argued that the gauge anomaly can be canceled via coupling to the R-R chiral bosons in bulk IIB string. We find that for a generic choice of the Fayet-Iliopoulos parameters on the world volume, the Higgs moduli space is a smooth fourfold birational to the original Calabi-Yau fourfold, but is not necessarily a Calabi-Yau manifold.
We investigate D=4, N=1 F theory models realized by type IIB string compactification on toric threefolds. Massless spectra, gauge symmetries, phase transitions associated with divisor contractions and flops, and non-perturbative superpotentials are analyzed using elementary toric methods.
A residue formula which evaluates any correlation function of topological $SU_n$ Yang-Mills theory with arbitrary magnetic flux insertion in two dimensions are obtained. Deformations of the system by two form operators are investigated in some detail. The method of the diagonalization of a matrix valued field turns out to be useful to compute various physical quantities. As an application we find the operator that contracts a handle of a Riemann surface and a genus recursion relation.
Several aspects of (0,2) Landau-Ginzburg orbifolds are investigated. Especially the elliptic genera are computed in general and, for a class of models recently invented by Distler and Kachru, they are compared with the ones from (0,2) sigma models. Our formalism gives an easy way to calculate the generation numbers for lots of Distler-Kachru models even if they are based on singular Calabi-Yau spaces. We also make some general remarks on the Born-Oppenheimer calculation of the ground states elucidating its mathematical meaning in the untwisted sector. For Distler-Kachru models based on non-singular Calabi-Yau spaces we show that there exist `residue' type formulas of the elliptic genera as well.
We investigate $N=2$ extended superconformal symmetry, using the half-twisted Landau-Ginzburg models. The first example is the $D_{2n+2}$ -type minimal model. It has been conjectured that this model has a spin $n$ super $W$ current. We checked this by the direct computations of the BRS cohomology class up to $n=4$. We observe for $n\le 3$ the super W currents generate the ring isomorphic to the chiral ring of the model with respect to the classical product. We thus conjecture that this isomorphism holds for any $n$. The next example is $ CP_{n}$ coset model. In this case we find a sort of Miura transformation which gives the simple formula for the super W currents of spin \{1,2,...,n\} in terms of the chiral superfields. Explicit form of the super W currents and their Poisson brackets are obtained for $CP_{2},CP_{3}$ case. We also conjecture that as long as the classical product is concerned, these super W currents generate the ring isomorphic to the chiral ring of the model and this is checked for $CP_2$ model.