Introduction. Operational quantum logic: An overview B. Coecke, et al. I: Algebras. Algebraic aspects of orthomodular lattices G. Bruns, J. Harding. Observables in the logico-algebraic approach P. Ptak. Test spaces and orthoalgebras A. Wilce. Representations on unigroups D.J. Foulis. Free extensions of group actions, induced representations, and the foundations of physics D.J. Foulis, A. Wilce. II: Categories. Short introduction to enriched categories F. Borceux, I. Stubbe. Operational Galois adjunctions B. Coecke, D. Moore. Operational axiomatics and compound systems F. Valckenborgh. Quantales J. Paseka, J. Rosicky. III: Languages. Quantales and observational semantics P. Resende. Quantum languages S. Gudder. Indices. Concept index. Citation index.
The paper is the contribution to quantum toposophy focusing on the abstract orthomodular structures (following Dunn-Moss-Wang terminology). Early quantum toposophical approach to "abstract quantum logic" was proposed based on the topos of functors
[E,Sets] where
E is a so-called orthomodular preorder category – a modification of categorically rewritten orthomodular lattice (taking into account that like any lattice it will be a finite co-complete preorder category). In the paper another kind of categorical semantics of quantum logic is discussed which is based on the modification of the topos construction itself – so called
quantos – which would be evaluated as a non-classical modification of topos with some extra structure allowing to take into consideration the peculiarity of negation in orthomodular quantum logic. The algebra of subobjects of quantos is not the Heyting algebra but an orthomodular lattice. Quantoses might be apprehended as an abstract reflection of Landsman's proposal of "Bohrification", i.e., the mathematical interpretation of Bohr's classical concepts by commutative
C∗-algebras, which in turn are studied in their quantum habitat of noncommutative
C∗-algebras – more fundamental structures than commutative
C∗-algebras. The Bohrification suggests that topos-theoretic approach also should be modified. Since topos by its nature is an intuitionistic construction then Bohrification in abstract case should be transformed in an application of categorical structure based on an orthomodular lattice which is more general construction than Heyting algebra – orthomodular lattices are non-distributive while Heyting algebras are distributive ones. Toposes thus should be studied in their quantum habitat of "orthomodular" categories i.e. of quntoses. Also an interpretation of some well-known systems of orthomodular quantum logic in quantos of functors
[E,QSets] is constructed where
QSets is a quantos (not a topos) of quantum sets. The completeness of those systems in respect to the semantics proposed is proved.
The concept of an operational logic has been developed by Randall and Foulis ([l]-[4], [10], [11]) as a part of a larger effort to obtain a formalism suitable for expressing, comparing, and evaluating various approaches to empirical science, statistics, and in particular, quantum mechanics. The structure of these logics is similar to that of an orthomodular partially ordered set which is often used as a model for quantum logics. However, the operational logic is a more general structure which, among other features, allows for the creation of a tensor product of logics to represent the coupling of physical systems. Randall and Foulis have shown that, given certain reasonable physical constraints, such a product is not possible within the category of orthomodular posets [12].