Basic randomness of nature and ether-drift experiments

We re-consider the idea that quantum fluctuations might reflect the existence of an ‘objectiverandomness’, i.e. a basic property of the vacuum state which is independent of anyexperimental accuracy of the observations or limited knowledge of initial conditions.Besides being responsible for the observed quantum behavior, this might introduce a weak,residual form of ‘noise’ which is intrinsic to natural phenomena and could be important forthe emergence of complexity at higher physical levels. By adopting Stochastic ElectroDynamics as a heuristic model, we are driven to a picture of the vacuum as a form of highlyturbulent ether, which is deep-rooted into the basic foundational aspects of both quantumphysics and relativity, and to search for experimental tests of this scenario. An analysis ofthe most precise ether-drift experiments, operating both at room temperature and in thecryogenic regime, shows that, at present, there is some ambiguity in the interpretationof the data. In fact the average amplitude of the signal has precisely the magnitudeexpected, in a ‘Lorentzian’ form of relativity, from an underlying stochastic ether and, assuch, might not be a spurious instrumental effect. This puzzle, however, should be solvedin a next future with the use of new cryogenically cooled optical resonators whose stabilityshould improve by about two orders of magnitude. In these new experimental conditions,the persistence of the present amplitude would represent a clean evidence for the type ofrandom vacuum we are envisaging.