No Hilbert Einstein Action With Positive Dark Energy / Cosmological Constant From A String Action

The paper revisits our past analysis of the ability of superstrings to model vacua with positive cosmological constant/dark energy effects. We explicitly call out the impossibility for superstrings to recover the Hilbert Einstein action, or de Sitter (stable, metastable or unstable) vacua with positive cosmological constant, or time-varying effects.