Positive Definite Gravitational Action, Cosmological Constant and Superstring Theory

Abstract

We use the recently discovered universality of Einstein equations in the first order formalism to suggest a positive definite Euclidean action. Possible implications for quantum gravity are considered. We discuss the Hawking and Coleman approach to the vanishing of the cosmological constant by using the new action and find that the cosmological constant is probably zero. A possible scenario for obtaining such an action from superstring field theory is discussed.