Unveiling the nature of quantum reality: a theoretical and experimental approach employing non-destructive weak measurements

Despite the huge predictive success of quantum theory, the very nature of the physical reality described by the formalism still remains obscure. The reason is that, on the one hand, we still don't know the relationship between the theoretical entities of the theory and physical reality (nor for that matter whether the theoretical terms refer at all to aspects of physical reality), while on the other hand observations made on quantum systems are invasive, changing the state of the quantum system, and generally destructive. The aim of our proposal is to explore, both theoretically and experimentally, aspects of this elusive reality. We will focus on two main issues. 1) Disembodiment of a particle property: it was recently realized that the formalism predicts that a property of a quantum system can be spatially separated from the location where the system itself can be found; 2) The dynamics underlying the evolution of a quantum system: the main theoretical term of quantum theory from which all the predictions are made – the state vector or wave function – propagates mathematically by taking all the available paths; but is this a physical feature, i.e. is it also the case “in reality”? We will base our investigations on theoretical schemes introduced very recently that aim to extract information on the properties of a quantum system in a non-invasive manner, without destroying its evolution. The theoretical work will lead to suggest experiments in order to observe the disembodiment and the underlying dynamics of a single photon. We plan to perform the experiments with optical interferometric setups employing state of the art entangled and heralded single photon sources. Finally we will appraise the results and analyze the implications for the nature of the reality of the quantum world.