24 research outputs found
Causality, particle localization and positivity of the energy
Positivity of the Hamiltonian alone is used to show that particles, if
initially localized in a finite region, immediately develop infinite tails.Comment: To appear in: Irreversibility and Causality in Quantum Theory --
Semigroups and Rigged Hilbert Spaces, edited by A. Bohm, H.-D. Doebner and P.
Kielanowski, Springer Lecture Notes in Physics, Vol. 504 (1998
Quantum Experimental Data in Psychology and Economics
We prove a theorem which shows that a collection of experimental data of
probabilistic weights related to decisions with respect to situations and their
disjunction cannot be modeled within a classical probabilistic weight structure
in case the experimental data contain the effect referred to as the
'disjunction effect' in psychology. We identify different experimental
situations in psychology, more specifically in concept theory and in decision
theory, and in economics (namely situations where Savage's Sure-Thing Principle
is violated) where the disjunction effect appears and we point out the common
nature of the effect. We analyze how our theorem constitutes a no-go theorem
for classical probabilistic weight structures for common experimental data when
the disjunction effect is affecting the values of these data. We put forward a
simple geometric criterion that reveals the non classicality of the considered
probabilistic weights and we illustrate our geometrical criterion by means of
experimentally measured membership weights of items with respect to pairs of
concepts and their disjunctions. The violation of the classical probabilistic
weight structure is very analogous to the violation of the well-known Bell
inequalities studied in quantum mechanics. The no-go theorem we prove in the
present article with respect to the collection of experimental data we consider
has a status analogous to the well known no-go theorems for hidden variable
theories in quantum mechanics with respect to experimental data obtained in
quantum laboratories. For this reason our analysis puts forward a strong
argument in favor of the validity of using a quantum formalism for modeling the
considered psychological experimental data as considered in this paper.Comment: 15 pages, 4 figure
Is symmetry identity?
Wigner found unreasonable the "effectiveness of mathematics in the natural
sciences". But if the mathematics we use to describe nature is simply a coded
expression of our experience then its effectiveness is quite reasonable. Its
effectiveness is built into its design. We consider group theory, the logic of
symmetry. We examine the premise that symmetry is identity; that group theory
encodes our experience of identification. To decide whether group theory
describes the world in such an elemental way we catalogue the detailed
correspondence between elements of the physical world and elements of the
formalism. Providing an unequivocal match between concept and mathematical
statement completes the case. It makes effectiveness appear reasonable. The
case that symmetry is identity is a strong one but it is not complete. The
further validation required suggests that unexpected entities might be
describable by the irreducible representations of group theory
Agroforestry : preliminary results of intercropping Acacia, Eucalyptus, and Leucaena with maize and beans
Meeting: Symposium on Intercropping in Semi-Arid Areas, 2d, 4-7 Aug. 1980, Morogoro, TZIn IDL-391