arXiv subjects

Yűji Ohta

Publications and source records attributed to Yűji Ohta.

3 recordsLinked to original sources

arXiv1997

Topological Field Theories associated with Three Dimensional Seiberg-Witten monopoles

Three dimensional topological field theories associated with the three dimensional version of Abelian and non-Abelian Seiberg-Witten monopoles are presented. These three dimensional monopole equations are obtained by a dimensional reduction of the four dimensional ones. The starting actions to be considered are Gaussian types with random auxiliary fields. As the local gauge symmetries with topological shifts are found to be first stage reducible, Batalin-Vilkovisky algorithm is suitable for quantization. Then BRST transformation rules are automatically obtained. Non-trivial observables associated with Chern classes are obtained from geometric sector and are found to correspond to those of the topological field theory of Bogomol'nyi monopoles.

hep-th↗

arXiv1996

Prepotential of N=2 SU(2) Yang-Mills gauge theory coupled with a massive matter multiplet

We discuss the N=2 SU(2) Yang-Mills theory coupled with a massive matter in the weak coupling. In particular, we obtain the instanton expansion of its prepotential. Instanton contributions in the mass-less limit are completely reproduced. We study also the double scaling limit of this massive theory and find that the prepotential with instanton corrections in the double scaling limit coincides with that of N=2 SU(2) Yang-Mills theory without matter.

hep-th↗

arXiv1995

Topological Strings with Scaling Violation and Toda Lattice Hierarchy

We show that there is a series of topological string theories whose integrable structure is described by the Toda lattice hierarchy. The monodromy group of the Frobenius manifold for the matter sector is an extension of the affine Weyl group $\widetilde W (A_N^{(1)})$ introduced by Dubrovin. These models are generalizations of the topological $CP^1$ string theory with scaling violation. The logarithmic Hamiltonians generate flows for the puncture operator and its descendants. We derive the string equation from the constraints on the Lax and the Orlov operators. The constraints are of different type from those for the $c=1$ string theory. Higher genus expansion is obtained by considering the Lax operator in matrix form.

hep-th↗