Quantum Logics with Given Centers and Variable State Spaces

We ask which logics with a given center allowfor enlargements with an arbitrary state space. We showthat these are precisely those logics the center ofwhich possesses a two-valued state and the state space of which is nonempty. This extends theresults of Binder as well as our previous results andsupplements the results of Foulis and Ptak and ofNavara, Ptak, and Rogalewicz. We also comment on some related questions.     

Greechie Diagrams of Small Quantum Logics with Small State Spaces

We present Greechie diagrams of various quantumlogics with small state spaces (i.e., the set oftwo-valued states is empty, not unital, not separating,not full, resp.). We present the smallest known examples of such so-called Kochen-Specker typeconstructions.     

Quantum Logics and Instruments

In a combined quantum logic and convexityapproach, an abstract notion of an instrument (statetransformer) is introduced to describe quantummeasurements. Some important classes of instruments(first kind, repeatable, ideal, Luders) and relations amongthem are investigated.     

Concrete Quantum Logics

Concrete quantum logics are quantum logics which allow for a set representation.They seem to be of significant conceptual value within quantum axiomatics andthey play an important role in the theory of orthomodular structures asset-representable orthomodular posets or lattices and they also sometimes constitutea domain for investigations in noncommutative. measure theory. This paperpresents a survey of recent results on this class of logics. Stress is put on thealgebraic and measure-theoretic aspects. Several open questions relevant tothe logicoalgebraic foundation of quantum theories are posed.     

Fock Theories and Quantum Logics

The notion of Fock theory is introduced in the framework of quantum logics, which are here orthomodular atomic lattices satisfying the covering property. It is shown that there are some fundamental facts concerning particles, which may be successfully discussed in this general context. One of these facts is to establish the theoretical conditions for considering particles as sharply defined entities. The other refers to the theoretical circumstances, which almost impose to consider that some particles have a structure, meaning they are composed from other particles. This last problem is strongly related with the conservative time evolutions.     

Towards Quantum Computational Logics

Quantum computational logics have recently stirred increasing attention (Cattaneo et al. in Math. Slovaca 54:87–108, 2004; Ledda et al. in Stud. Log. 82(2):245–270, 2006; Giuntini et al. in Stud. Log. 87(1):99–128, 2007). In this paper we outline their motivations and report on the state of the art of the approach to the logic of quantum computation that has been recently taken up and developed by our research group.     

Quantum Logics and Relative Lindenbaum Property

The relative Lindenbaum property is considered in orthomodular quantum logic and in partial class ical logic. The properties of these models are connected with the possibility of hidden-variable reconstruction of particular (1/2-spin particle e.g.) quantum physical systems.     

Quantum Computational Logics and Possible Applications

In quantum computational logics meanings of formulas are identified with quantum information quantities: systems of qubits or, more generally, mixtures of systems of qubits. We consider two kinds of quantum computational semantics: (1) a compositional semantics, where the meaning of a compound formula is determined by the meanings of its parts; (2) a holistic semantics, which makes essential use of the characteristic “holistic” features of the quantum-theoretic formalism. The compositional and the holistic semantics turn out to characterize the same logic. In this framework, one can introduce the notion of quantum-classical truth table, which corresponds to the most natural way for a quantum computer to calculate classical tautologies. Quantum computational logics can be applied to investigate different kinds of semantic phenomena where holistic, contextual and gestaltic patterns play an essential role (from natural languages to musical compositions).     

Spectral Automorphisms in Quantum Logics

In quantum mechanics, the Hilbert space formalism might be physically justified in terms of some axioms based on the orthomodular lattice (OML) mathematical structure (Piron in Foundations of Quantum Physics, Benjamin, Reading, 1976). We intend to investigate the extent to which some fundamental physical facts can be described in the more general framework of OMLs, without the support of Hilbert space-specific tools. We consider the study of lattice automorphisms properties as a “substitute” for Hilbert space techniques in investigating the spectral properties of observables. This is why we introduce the notion of spectral automorphism of an OML. Properties of spectral automorphisms and of their spectra are studied. We prove that the presence of nontrivial spectral automorphisms allow us to distinguish between classical and nonclassical theories. We also prove, for finite dimensional OMLs, that for every spectral automorphism there is a basis of invariant atoms. This is an analogue of the spectral theorem for unitary operators having purely point spectrum.     

Convex Quantum Logic

In this work we study the convex set of quantum states from a quantum logical point of view. We consider an algebraic structure based on the convex subsets of this set. The relationship of this algebraic structure with the lattice of propositions of quantum logic is shown. This new structure is suitable for the study of compound systems and shows new differences between quantum and classical mechanics. These differences are linked to the nontrivial correlations which appear when quantum systems interact. They are reflected in the new propositional structure, and do not have a classical analogue. This approach is also suitable for an algebraic characterization of entanglement and it provides a new entanglement criteria.     

Quantum Logics that are Symmetric-difference-closed

International Journal of Theoretical Physics - In this note we contribute to the recently developing study of “almost Boolean” quantum logics (i.e. to the study of orthomodular...     

Order Topology Orthosummability in Quantum Logics

By using the Antosik–Mikusinski infinite matrix convergence theorem in quantum logics, we prove a theorem on orthosummability with respect to order topology in quantum logics.     

Quantum Conservative Gates for Finite-Valued Logics

We introduce some conservative gates for finite-valued logics which are able to realize all the main connectives of the many-valued logics of ?ukasiewicz, the MV-algebras of Chang and Brower–Zadeh algebras. After a brief exposition of the motivations for this work, the gates are defined and their properties are explored. Finally, a possible quantum realization of them is proposed, using three techniques: a “brute force” method--an extension of the Conditional Quantum Control argument, and a new technique which we call the Constants Method. For all these techniques, the unitary operator which describes the gate is a sum of local operators.     

Lattice Properties of Ring-like Quantum Logics

Generalized Boolean quasirings (GBQRs) are extensions of partial algebras thatare in one-to-one correspondence to bounded lattices with an involutoryantiautomorphism. This correspondence generalizes the bijection betweenBoolean rings and Boolean algebras and provides for a large variety of presumptivequantum logics (including logics which can be defined by means of Mackey'sprobability function). It is shown how properties of the corresponding latticesare reflected in GBQRs and what the implications are of the associativity of the+-operation of GBQRs, which can be interpreted as some kind of an exclusiveor-operation. We prove that under very weak conditions, which, however, seemto be essential for experimental verifications, the associativity of + implies theclassicality of the considered quantum mechanical system.     

Recent Progress on Pre-Hilbert-Space Logics and Their Measure Spaces

The aim of this survey paper is to summarize the most recent results on pre-Hilbert-space logics and their corresponding measure spaces. PACS: 02.10. The paper is dedicated to the memory of Prof. Günter Bruns.     

Fuzzy Quantum Logics as a Basis for Quantum Probability Theory

Representation of an abstract quantum logic withan ordering set of states S in the form of a family L(S) of fuzzy subsets of S which fulfils conditionsanalogous to Kolmogorovian conditions imposed on -algebra of random events allows us toconstruct quantum probability calculus in a waycompletely parallel to the classical Kolmogorovianprobability calculus. It is shown that the quantumprobability calculus so constructed is a propergeneralization of the classical Kolmogorovian one. Someindications for building a phase-space representation ofquantum mechanics free of the problem of negativeprobabilities are given.     

Quantum Spinor Structures for Quantum Spaces

A general theory of quantum spinor structures on quantum spaces is presented within the formalism of quantum principal bundles. Quantum analogs of basic objects of the classical theory are constructed: Laplace and Dirac operators, quantum versions of Clifford and spinor bundles, a Hodge *-operator, integration operators. Quantum phenomena are discussed, including an example of the Dirac operator associated to a quantum Hopf fibration.     

Hidden Variables and Bell Inequalities on Quantum Logics

In the quantum logic approach, Bell inequalities in the sense of Pitowski are related with quasi hidden variables in the sense of Deliyannis. Some properties of hidden variables on effect algebras are discussed.