Space–time curvature due to quantum vacuum fluctuations: An alternative to dark energy?

It is pointed out that quantum vacuum fluctuations may give rise to a curvature of space–time equivalent to the curvature currently attributed to dark energy. A simple calculation is made, involving plausible assumptions within the framework of quantized gravity, which suggests that the value of the dark energy density is roughly given by the product of Newton's constant times the quantity m6c4ℏ−4m6c4ℏ−4, m being a typical mass of elementary particles. The estimate is compatible with observations.