Quantum noise in time-dependent media and cosmic expansion

In astrophysics, cracks have appeared in the cosmological standard model. Now, this new paper in condensed matter physics suggests a surprisingly simple fix. The authors develop here a theory for calculating the energy of quantum fluctuations in spatially homogeneous but time-depending media. The expanding universe acts as such a medium. The authors show that in this ``medium of space'' each ingredient of the cosmic mix get a little lighter as if it were partially buoyant in the sea of the vacuum.