CONICET | Buscador de Institutos y Recursos Humanos

The interpretation of reduced states as quantum states is a common practice in physics. The aim of this paper is to reject this usual interpretation on the basis of a twofold argument. First, we will argue that the reduced state of a decohering system is a coarse-grained state, analogous to the coarsegrained descriptions of unstable classical systems. Second, in the context of no-collapse interpretations we will show that, even in the case of non-interacting subsystems, the move of conceiving their reduced states as their legitimate quantum states precludes the account of consecutive measurements.