Moduli of spin curves and spin quantum cohomology

Arkady Vaintrob (University of Oregon)



We review recent progress on the generalized Witten conjecture that relates intersection theory on the moduli spaces of higher spin curves and the Gelfand-Dickey integrable hierarchies. We discuss this conjecture and its main ingredients from the point of view of cohomological field theories. Then we introduce the moduli spaces of so-called stable spin maps into a variety V and the spin Gromov-Witten classes associated to them.  Restricting to genus zero, this gives the spin quantum cohomology of V whose Frobenius structure is isomorphic to the tensor product of the Frobenius manifolds associated to ordinary quantum cohomology of V and the Gelfand-Dickey hierarchy (or, equivalently, the simple singularity of type Ar).

OPEN PROBLEMS RELATED TO MODULI OF HIGHER SPIN CURVES AND SPIN QUANTUM COHOMOLOGY

  1. Prove the generalized Witten's conjecture relating the intersection theory on the moduli spaces of r-spin curves and the r-th Gelfand-Dickey integrable hierarchy.

  2. Quantum cohomology and Gromov-Witten invariants of a variety V have an interpretation from the point of view of enumerative geometry - they "count" curves on V satisfying certain conditions. Find an enumerative interpretation of the spin quantum cohomology and spin Gromov-Witten invariants of V.

  3. Another conjecture of Witten asserts that the generating function F of the descendant Gromov-Witten invariants of V (the so-called partition function of the gravitational quantum cohomology of V) is annihilated by certain differential operators Li satisfying the commutation relations of the Virasoro algebra. The (still conjectural) explicit form  of this operators was suggested by Eguchi, Hori, Xiong and Katz. This Virasoro conjecture has been proved only when V is a point, and also for more general classes of V for genus zero and one invariants.

    The corresponding partition function in the case of the r-spin theory should be annihilated by a larger collection of operators satisfying the relations of the so-called Wr-algebra. Explicit formulas for these operators are known in the case when V is a point (and the corresponding Virasoro conjecture is equivalent to the generalized Witten conjecture of Problem 1).

    Find the r-spin analogs of the Eguchi-Hori-Xiong-Katz formula and prove the corresponding Wr - conjecture (at least for genus zero and one invariants).

  4. The generalized Witten's conjecture and theory of spin quantum cohomology are related to a physical model of two-dimensional gravity with the gauge group of type Ar.

    Find analogs of r-spin curves and the (conjectural) formulas connecting the corresponding moduli spaces with the Drinfeld-Sokolov generalizations of the Gelfand-Dickey equations for series D and E.

Fall 2000 meeting of the PNGS