Volume 4, Issue 4, pages 247-267
Oimpia Lombardi obtained her degree in Electronic Engineering and in Philosophy at the University of Buenos Aires, and her PhD in Philosophy at the same university. She is Principal Researcher at the National Scientific and Technical Research Council of Argentina. She is member of the Academie Internationale de Philosophie des Sciences and of the Foundational Questions Institute. She is the director of the Group of the Philosohy of Science at the University of Buenos Aires. Areas of interest: foundations of statistical mechanics, the problem of the arrow of time, interpretation of quantum mechanics, the nature of information, philosophy of chemistry.
Sebastian Fortin has a degree and a PhD in Physics at the University of Buenos Aires and a PhD in Epistemology and History of Science at the National University of Tres de Febrero, Argentina. He is Researcher at the National Scientific and Technical Research Council of Argentina and assistant professor at the Physics Department of the Faculty of Exact and Natural Sciences at the University of Buenos Aires. His field of interest is philosophy of physics, particularly foundations of quantum mechanics.
If decoherence is an irreversible process, its physical meaning might be clarified by comparing quantum and classical irreversibility. In this work we carry out this comparison, from which a unified view of the emergence of irreversibility arises, applicable both to the classical and to the quantum case. According to this unified view, in the two cases the irreversible macro-level arises from the reversible micro-level as a coarse description that can be understood in terms of the concept of projection. This position supplies an understanding of the phenomenon of decoherence different from that implicit in most presentations: the reduced state is not the quantum state of the open system, but a coarse state of the closed composite system; as a consequence, decoherence should be understood not as a phenomenon resulting from the interaction between an open system and its environment, but rather as a coarse evolution that emerges from disregarding certain degrees of freedom of the whole closed system.