A general conceptual framework for decoherence in closed and open systems

MARIO CASTAGNINO; ROBERTO LAURA; OLIMPIA LOMBARDI

Vancouver

Congreso; Twentieth Biennial Meeting of the Philosophy of Science Association; 2006

Philosophy of Science Association

At present, the theory of environment-induced decoherence (EID) is considered a “new orthodoxy” in the quantum physicists community (Bub 1997).  In fact, EID has been fruitfully applied in many areas of physics and supplies the basis of new technological developments (see Joos et. al 2003l).  In the field of the philosophy of physics, EID has been considered as a relevant element for the interpretation of quantum mechanics (see Bacciagaluppi and Hemmo 1994, 1996), in particular, for the explanation of the emergence of classicity from an underlying quantum world (Elby 1994, Healey 1995). The great success of EID has given rise to the idea that decoherence is a process that necessarily requires que interaction between a quantum system and an environment of many, potentially infinite, degrees of freedom.  However, when the issue is viewed from an historical perspective, the roots of the decoherence program can be found in certain attempts to explain the emergence of classicality in closed systems.  In turn, at present other approaches to decoherence have been proposed, and in several of them the openess of the system is not an essential or decisive factor.  These new approaches are usually conceived as rival to EID or even as theories dealing with a different physical phenomenon. The aim of this paper is to argue that this is not the case; on the contrary, formalisms originally devised to deal jus with closed or open systems can be subsumed under a general conceptual framework, which clarifies the very nature of the phenomenon of decoherence.  In particular, we will show that , from the new perspective, both kinds of approaches can be viewed as complementary in the understanding of the same physical phenomenon.  This task will allow us to conclude that the openness of the quantum system is not the essential ingredient for decoherence, as commonly claimed, but also to dissolve certain conceptual difficulties that threaten  the conceptual foundations of the EID program.