Rationality, universal generation and the integral Hodge conjecture

Abstract

We use the universal generation of algebraic cycles to relate (stable) rationality to the integral Hodge conjecture. We show that the Chow group of 1-cycles on a cubic hypersurface is universally generated by lines. Applications are mainly in cubic hypersurfaces of low dimensions. For example, we show that if a generic cubic fourfold is stably rational then the Beauville--Bogomolov form on its variety of lines, viewed as an integral Hodge class on the self product of its variety of lines, is algebraic. In dimension $3$ and $5$, we relate stable rationality with the geometry of the associated intermediate Jacobian.

Revised version

References in corpus (1)

• Stable rationality of cyclic covers of projective spaces

Cited by in corpus (3)

• On the integral Hodge conjecture for real varieties, II
• On the coniveau of rationally connected threefolds
• Cylinder maps of algebraic cycles on cubic hypersurfaces