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Toshiya Kawai

Publications and source records attributed to Toshiya Kawai.

14 recordsLinked to original sources
arXiv2009

Twisted Elliptic Genera of N=2 SCFTs in Two Dimensions

The elliptic genera of two-dimensional N=2 superconformal field theories can be twisted by the action of the integral Heisenberg group if their U(1) charges are fractional. The basic properties of the resulting twisted elliptic genera and the associated twisted Witten indices are investigated with due attention to their behaviors in orbifoldization. Our findings are illustrated by and applied to several concrete examples. We give a better understanding of the duality phenomenon observed long before for certain Landau-Ginzburg models. We revisit and prove an old conjecture of Witten which states that every ADE Landau-Ginzburg model and the corresponding minimal model share the same elliptic genus. Mathematically, we establish ADE generalizations of the quintuple product identity.

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arXiv2009

Abelian Vortices on Nodal and Cuspidal Curves

We compute the Euler characteristics of the moduli spaces of abelian vortices on curves with nodal and cuspidal singularities. This generalizes our previous work where only nodes were taken into account. The result we obtain is again consistent with the expected reconciliation between the vortex picture of D2-D0 branes and the proposal by Gopakumar and Vafa.

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arXiv2004

String and Vortex

We discuss how the geometry of $D2$-$D0$ branes may be related to Gromov-Witten theory of Calabi-Yau threefolds.

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arXiv2000

String Partition Functions and Infinite Products

We continue to explore the conjectural expressions of the Gromov-Witten potentials for a class of elliptically and K3 fibered Calabi-Yau 3-folds in the limit where the base P^1 of the K3 fibration becomes infinitely large. At least in this limit we argue that the string partition function (=the exponential generating function of the Gromov-Witten potentials) can be expressed as an infinite product in which the Kahler moduli and the string coupling are treated somewhat on an equal footing. Technically speaking, we use the exponential lifting of a weight zero Jacobi form to reach the infinite product as in the celebrated work of Borcherds. However, the relevant Jacobi form is associated with a lattice of Lorentzian signature. A major part of this work is devoted to an attempt to interpret the infinite product or more precisely the Jacobi form in terms of the bound states of D2- and D0-branes using a vortex description and its suitable generalization.

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arXiv1998

String Duality and Enumeration of Curves by Jacobi Forms

For a Calabi-Yau threefold admitting both a $K3$ fibration and an elliptic fibration (with some extra conditions) we discuss candidate asymptotic expressions of the genus 0 and 1 Gromov-Witten potentials in the limit (possibly corresponding to the perturbative regime of a heterotic string) where the area of the base of the $K3$ fibration is very large. The expressions are constructed by lifting procedures using nearly holomorphic Weyl-invariant Jacobi forms. The method we use is similar to the one introduced by Borcherds for the constructions of automorphic forms on type IV domains as infinite products and employs in an essential way the elliptic polylogarithms of Beilinson and Levin. In particular, if we take a further limit where the base of the elliptic fibration decompactifies, the Gromov-Witten potentials are expressed simply by these elliptic polylogarithms. The theta correspondence considered by Harvey and Moore which they used to extract the expression for the perturbative prepotential is closely related to the Eisenstein-Kronecker double series and hence the real versions of elliptic polylogarithms introduced by Zagier.

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arXiv1997

K3 Surfaces, Igusa Cusp Form and String Theory

It has recently become apparent that the elliptic genera of K3 surfaces (and their symmetric products) are intimately related to the Igusa cusp form of weight ten. In this contribution, I survey this connection with an emphasis on string theoretic viewpoints.

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arXiv1997

String Duality and Modular Forms

Tests of duality between heterotic strings on $K3\times T^2$ (restricted on certain Narain moduli subspaces) and type IIA strings on K3-fibered Calabi-Yau threefolds are attempted in the weak coupling regime on the heterotic side by identifying pertinent modular forms related to the computations of string threshold corrections. Concretely we discuss in parallel the three cases associated with Calabi-Yau manifolds $(A):X(6,2,2,1,1)_{2}^{-252}$, $(B):X(12,8,2,1,1)_{3}^{-480}$ and $(C):X(10,3,3,2,2)_{4}^{-132}$ on the type IIA side.

hep-th↗
arXiv1995

$N=2$ heterotic string threshold correction, $K3$ surface and generalized Kac-Moody superalgebra

We study a standard-embedding $N=2$ heterotic string compactification on $K3\times T^2$ with a Wilson line turned on and perform a world-sheet calculation of string threshold correction. The result can be expressed in terms of the quantities appearing in the two-loop calculation of bosonic string. We also comment and speculate on the relevance of our result to generalized Kac-Moody superalgebra and $N=2$ heterotic-type IIA duality.

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arXiv1994

Duality of Orbifoldized Elliptic Genera

We discuss duality and mirror symmetry phenomena of Landau-Ginzburg orbifolds considering their elliptic genera. Under the duality (or mirror) transform performed by orbifoldizing the Landau-Ginzburg model via some discrete group of the superpotential we observe that the roles of the untwisted and twisted sectors are exchanged. As explicit evidence detailed orbifold data are presented for $N=2$ minimal models, Arnold's exceptional singularities, $K3$ surfaces constructed from Arnold's singularities and Fermat hypersurfaces. (To appear in the proceedings of the workshop, ``Quantum Field Theory, Integrable Models and Beyond'', Yukawa Institute for Theoretical Physics, Kyoto University, 14-18 February 1994.)

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arXiv1994

Elliptic Genera of N=2 Hermitian Symmetric Space Models

Expressions are given for the elliptic genera of the Kazama-Suzuki models associated with hermitian symmetric spaces when the problems of field identifications are absent. We use the models' known Coulomb gas descriptions.

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arXiv1994

Geometry of (0,2) Landau-Ginzburg Orbifolds

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.

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arXiv1993

Elliptic Genera and N=2 Superconformal Field Theory

Recently Witten proposed to consider elliptic genus in $N=2$ superconformal field theory to understand the relation between $N=2$ minimal models and Landau-Ginzburg theories. In this paper we first discuss the basic properties satisfied by elliptic genera in $N=2$ theories. These properties are confirmed by some fundamental class of examples. Then we introduce a generic procedure to compute the elliptic genera of a particular class of orbifold theories, {\it i.e.\/} the ones orbifoldized by $e^{2πiJ_0}$ in the Neveu-Schwarz sector. This enables us to calculate the elliptic genera for Landau-Ginzburg orbifolds. When the Landau-Ginzburg orbifolds allow an interpretation as target manifolds with $SU(N)$ holonomy we can compare the expressions with the ones obtained by orbifoldizing tensor products of $N=2$ minimal models. We also give sigma model expressions of the elliptic genera for manifolds of $SU(N)$ holonomy.

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arXiv1992

Higher-Rank Supersymmetric Models and Topological Field Theory

In the first part of this paper we investigate the operator aspect of higher-rank supersymmetric model which is introduced as a Lie theoretic extension of the $N=2$ minimal model with the simplest case $su(2)$ corresponding to the $N=2$ minimal model. In particular we identify the analogs of chirality conditions and chiral ring. In the second part we construct a class of topological conformal field theories starting with this higher-rank supersymmetric model. We show the BRST-exactness of the twisted stress-energy tensor, find out physical observables and discuss how to make their correlation functions. It is emphasized that in the case of $su(2)$ the topological field theory constructed in this paper is distinct from the one obtained by twisting the $N=2$ minimal model through the usual procedure.

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