WORKSHOP ON THE PROBLEM OF QUANTUM MEASUREMENT 6-7 December, 1999, Eotvos University, Budapest Website: http://hps.elte.hu/Workshop/workshop.htm Organizers: Miklos Redei and Laszlo E. Szabo Department of History and Philosophy of Science, Eotvos University Sponsored by: Eotvos University Ministry of Education Stiftung Aktion Osterreich - Ungarn Austrian Science and Research Liaison Office ___________ The workshop consists of Keynote Addresses and Panel Discussions about the different approaches to the problem of quantum measurement. The emphasizes are laid upon the Panel Discussions; The Keynote Addresses are only aimed to sum up the main ideas of the most important approaches to the foundational questions of quantum mechanics, rather than to expound someone's personal views or results. P a n e l i s t s: GYULA BENE (Theoretical Physics, Eotvos, Budapest) THOMAS BREUER (Philosophy, Fachhochschule Vorarlberg) DENNIS DIEKS (Hist. and Found. of Math. and Natural Sci., Univ.of Utrecht) LAJOS DIOSI (Research Inst. for Particle and Nuclear Physics, Budapest) TAMAS GESZTI (Physics of Complex Systems, Eotvos, Budapest) BARRY LOEWER (Philosophy, Rutgers, New Jersey) TOMASZ PLACEK (Philosophy, University of Cracow) MIKLOS REDEI (HPS, Eotvos, Budapest) MICHAEL STOELTZNER (Institute of Vienna Circle, Vienna) LASZLO E. SZABO (Theor. Phys. and HPS, Eotvos, Budapest) PIETER VERMAAS (Philosophy, Delft University of Technology) GREGOR WEIHS (Experimental Physics, University of Vienna) Venue: Kari Tanacsterem, 7th floor, Eotvos University, Faculty of Science, Pazmany P. setany 1/A, Budapest. (About location: http://hps.elte.hu/dept/Location.htm) PROGRAM: 6 December, Monday 8:55 Opening KEYNOTE ADDRESSES Chairman: P. Vermaas 9:00 - 9:35 Neumann's theory of quantum measurement (Geszti) Break 9:45 - 10:20 The many world - many mind interpretation (Loewer) 10:20 - 11:00 The modal interpretations (Dieks) Coffee break 11:30 - 12:05 GRW and the likes (Diosi) Lunch Chairman: L. Diosi 14:00 - 14:30 The statistical interpretation (Szabo) 14:30 - 15:05 Decoherence theories (Bene) Coffee break DISCUSSION Chairman: M. Redei 15:35 - 16:40 /Break /16:55 -18:00 Can we agree on criteria a tenable interpretation of quantum mechanics should (minimally) satisfy? What is the ontological status of the wave function? Does an individual object have a wave function at all? If wave function is assigned to an individual object, in what sense does it represent probability distributions? If not, does it reflect anything objective about an individual system? How can we identify the system's wave function experimentally? If a wave function does represent a probability distribution, then what is it a probability distribution of? Can we talk about the system's wave function experimentally without any reference to classical concepts? 7 December, Tuesday DISCUSSION Chairman: M. Stoeltzner 9:00 -10:30 Is quantum measurement paradox the same problem as Schrodinger's cat? Is there any physical meaning of the fact that a quantum state is a superposition of other states, independently of the measurement problem? If the quantum state of a microscopic system is a\psi_A + b\psi_B, is it true that one or other of these states has been realized? And what if "microscopic" is replaced by "macroscopic"? Can we test superpositions experimentally? What happens when an outcome of a quantum measurement occurs? Does the wave function collapse? Are the following terms synonyms: 'to be in a quantum state', 'event', 'the state of the world/affairs', 'property', 'actualization of a potentiality', 'a variable takes value', 'property ascription', 'value assignment'? Is it true that before throwing a dice its wave function is a superposition of six wave functions belonging to the six numbers? Is quantum measurement a special kind of process or is it just one of the usual physical processes? Coffee break KEYNOTE ADDRESS Chairman: T. Geszti 11:00 - 11:30 Endophysical aspect of the quantum measurement problem (Breuer) DISCUSSION Chairman: G. Weihs 11:30 - 13:00 Is there anything particular in quantum measurements with respect to the epistemic status of measurements in general? Does measurement involve consciousness or mind in any way? Does indeed quantum cosmology pose a challenge for quantum measurement theory? Is there any difference between quantum mechanical statements about the whole universe and other (classical) statistical statements about the whole universe? Does universal validity of laws of QM imply that they must provide a detailed, "complete and exhaustive" description of physical processes? Should QM account for quantum measurement at all? Do the laws governing a system differ when you're inside the system from those you see when you look at the system from the outside? More particularly, can we formulate QM or other physical theory without any reference to directly observable (macroscopic) phenomena? Lunch DISCUSSION Chairman: T. Placek 15:00 - 16:30 What does it mean that a physical quantity "has a value"? Should the Kochen-Specker theorem be interpreted by saying that 1) some physical quantities have no value? 2) the system has no ontologically relevant intrinsic properties? When do we say that a system possesses a property? How to translate the following vocabulary into the terms of observations: actual and potential properties, sharp and non-sharp values, definite (and indefinite?) outcome? Do objective (ontologically relevant) properties of a (quantum) system (if there are any) supervene on "physical quantities" modeled by quantum observables? Or just the other way round? Why do we prefer to abuse our everyday logic with such sentences like "it is true that a specific fish weights 4 kilos, but it is neither true nor false that the same fish weights 5 kilos", rather than to accept superluminal causal effects? Coffee break DISCUSSION Chairman: D. Dieks 17:00 18:00 Should QM account for (at least the possibility of ) a consistent understanding of micro- and macrophysical world in terms of ontologically relevant properties of a system, or is it enough if it can consistently explain the measurement processes only? Do decoherence theories provide such explanation? Should QM account for the specific classical outcome of an experiment or the human impression that a specific classical outcome occurs? Should we forget the measurement paradox and the likes when we will have a local hidden variables theory? 18:00 - 18:30 Closing remarks (Vermaas) __________________________ PUBLICATION: The whole workshop will be taped. With the help of the tape-record we will put down a brief summary of the discussions and send it to the participants. All participants are asked to elaborate and type his own contribution. PRELIMINARY MATERIALS (Links and further papers are available on http://hps.elte.hu/Workshop/workshop.htm) - Quantum Measurement: Beyond Paradox (R. A. Healey and G. Hellman, eds.), Univ. of Minnesota Press, 1998 - Diosi: Emergence of Classicality: From Collapse Phenomenologies to Hybrid Dynamics - Diosi: On hybrid dynamics of the Copenhagen dichotomic world - Geszti: John von Neumann and the Foundations of Quantum mechanics - Redei: Von Neumann's concept of quantum logic - Szabo: Quantum measurement: on this side of paradox - Szabo: Critical reflections on quantum probability theory -- Laszlo E. Szabo Department of Theoretical Physics Department of History and Philosophy of Science Eotvos University, Budapest H-1518 Budapest, Pf. 32. Phone: (36-1)2090-555/6671 Fax: (36-1)372-2509 Home: (36-1)200-7318 http://hps.elte.hu/~leszabo