Higher order terms in an improved heterotic M theory

Understand

Curvature squared terms are added to a consistent formulation of supergravity on manifolds with boundary which is meant to represent the low energy limit of the strongly coupled heterotic string.

• These terms are necessary for the cancellation of gravitational anomalies and for reduction to lower dimensions with broken chiral symmetry.
• The consequences of anomaly cancellation when flux and extrinsic curvature terms are taken into account have yet to be fully exploited, but some implications for flux terms are discussed.