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Journal of Physics Conference Series

Some properties of effect algebra

Wei Li, Wen Han, Yiyue Sun, Jiangtao Li, Jiaying Wang

Published Aug 1, 2024• 0 citations
Publisher

Abstract

Abstract As a kind of algebraic structure, effect algebra is the foundation of quantum structure and quantum measurement. Sequential effect algebra is a special type of effect algebra that plays an important role in the fundamental research of Quantum Computation. Therefore, we study the related theory of effect algebra in this paper. Finally, four properties and special examples of effect algebra and sequence effect algebra are presented, as well as three properties of effect algebra level sum.

DOI
10.1088/1742-6596/2813/1/012020

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Abstract As a kind of algebraic structure, effect algebra is the foundation of quantum structure and quantum measurement. Sequential effect algebra is a special type of effect algebra that plays an important role in the fundamental research of Quantum Computation. Therefore, we study the related theory of effect algebra in this paper. Finally, four properties and special examples of effect algebra and sequence effect algebra are presented, as well as three properties of effect algebra level sum.
Our basic structure is a finite-dimensional complex Hilbert space HHH. We point out that the set of effects on HHH form a convex effect algebra. Although the set of operators on HHH also form a convex effect algebra, they have a more detailed structure. W introduce sequential products of effect and operations. Although these have already been studied, we introduce the new concept of sequential products of effects with operations and operations with effects. We then consider various special types of operations. After developing properties of these concepts, the results are generalized to include observables and instruments. In particular, sequential products of observables with instruments and instruments with observables are developed. Finally, we consider conditioning and coexistence of observables and instruments.
A quantum effect is an operator AAA on a complex Hilbert space HHH that satisfies 0≤A≤I0\leq A\leq I0≤A≤I, E(H){\cal E} (H)E(H) is the set of all quantum effects on HHH. In 2001, Professor Gudder and Nagy studied the sequential product A∘B=A1/2BA1/2A\circ B=A^{1/2}BA^{1/2}A∘B=A1/2BA1/2 of A,B∈E(H)A, B\in {\cal E}(H)A,B∈E(H). In 2005, Professor Gudder asked: Is A∘B=A1/2BA1/2A\circ B=A^{1/2}BA^{1/2}A∘B=A1/2BA1/2 the only sequential product on E(H){\cal E} (H)E(H)? Recently, Liu and Wu presented an example to show that the answer is negative. In this paper, firstly, we characterize some algebraic properties of the abstract sequential product on E(H){\cal E} (H)E(H); secondly, we present a general method for constructing sequential products on E(H){\cal E} (H)E(H); finally, we study some properties of the sequential products constructed by the method
Abstract The Hilbert space effect algebra is a fundamental mathematical structure which is used to describe unsharp quantum measurements in Ludwig’s formulation of quantum mechanics. Each effect represents a quantum (fuzzy) event. The relation of coexistence plays an important role in this theory, as it expresses when two quantum events can be measured together by applying a suitable apparatus. This paper’s first goal is to answer a very natural question about this relation, namely, when two effects are coexistent with exactly the same effects? The other main aim is to describe all automorphisms of the effect algebra with respect to the relation of coexistence. In particular, we will see that they can differ quite a lot from usual standard automorphisms, which appear for instance in Ludwig’s theorem. As a byproduct of our methods we also strengthen a theorem of Molnár.
Aim To introduce the logical definition of the horizontal sum of effect algebras and study the uniqueness of sequential products on effect algebra.Methods Using the definition of effect algebra,sequential effect algebra and the polar decomposition of operator.Results There exists an infinite number of sequential products on the horizontal sum HS(e(H),) of the Hilbert space effect algebra e(H) and .Conclusion An effect algebra admits an infinite number of sequential products.As a special effect algebra,orthoalgebra can be decomposed to the horizontal sum of sub-effect algebra.