The Broken Mirror Principle of quantum mechanics: the case of quantum hydrodynamics

We propose the Broken Mirror Principle of quantum mechanics, stating that the different interpretations of quantum mechanics can be exploited to detect quantum effects that are independent of the given interpretation. We illustrate it by focusing on the hydrodynamical formulation of quantum mechanics, which describes quantum particles as fluids, with a focus on simple quantum systems containing non-relativistic single or a pair of quantum particles. Using quantum hydrodynamics, we show how quantum particles can be described as classical fluids for a suitable shape of their wavefunction, how a suitable shape can obtain an effective mass for the particle, and how a suitable shape of the wavefunction of coupled particles generates a classical flow velocity of decoupled particles.