The Vacuum Energy Density and the Cosmological Constant. QED Beyond the Standard Description

We consider here the enhancement of the vector potential amplitude quantization beyond the standard description in QED in order to overcome the zero-point-energy singularity and we show that the contribution of the electromagnetic field ground state to the vacuum energy is in reasonable agreement with the experimental observations contributing consequently to the cosmological constant. This approach confers a basic property to the quantum vacuum permitting to progress towards the understanding of the physical mechanisms responsible for the observed cosmic acceleration.