Geometric transitions, Chern-Simons gauge theory and Veneziano type amplitudes
Tohru Eguchi, Hiroaki Kanno
TL;DR
The paper shows that all-genus topological string amplitudes for certain local Calabi-Yau manifolds arising from geometric transitions can be computed via a free-field operator framework in 2D CFT. By representing Schur and skew Schur functions with vertex operators and exploiting the boson-fermion correspondence, the authors recast Chern-Simons Hopf link invariants and topological vertices as vacuum expectations of products of vertex operators, yielding Veneziano-like amplitudes. A key result is the expression $K^{SU(N)}_{\{R_i\}} = \prod_{i=1}^N \dim_q R_i \cdot \langle 0 | \prod_{k=1}^N V_-^{[R_k^t]}(q) V_+^{[R_k]}(q) Q_k^{L_0} | 0 \rangle$, which reproduces Nekrasov's all-genus formula for $SU(N)$ gauge theories. The approach highlights a simple free-field structure underlying all-genus topological string amplitudes and suggests avenues for extending to compact Calabi-Yau and Fano geometries.
Abstract
We consider the geometric transition and compute the all-genus topological string amplitudes expressed in terms of Hopf link invariants and topological vertices of Chern-Simons gauge theory. We introduce an operator technique of 2-dimensional CFT which greatly simplifies the computations. We in particular show that in the case of local Calabi-Yau manifolds described by toric geometry basic amplitudes are written as vacuum expectation values of a product vertex operators and thus appear quite similar to the Veneziano amplitudes of the old dual resonance models. Topological string amplitudes can be easily evaluated using vertex operator algebra.
