Quantum violations of joint reality

Abstract

With basis on (i) the physical principle of local causality and (ii) a certain notion of elements of reality, Einstein, Podolsky, and Rosen (EPR) put forward an argument showing that physical instances may exist in which two non-commuting observables can be joint elements of the physical reality. Here, we introduce a new criterion of joint reality. We demonstrate that, according to this criterion, quantum mechanics generally prevents non-commuting observables from having joint elements of reality. joint elements of reality. In addition, we introduce a measure to quantify the extent to which the criterion is violated and explore the implications of such a measure in connection with incompatibility and correlations. Our findings suggest new manners of interpreting quantum phenomena.