Copenhagen—Roles in Quantum Mechanics

Richard Joseph Oldani

Seyyed Hedayat Sajadi

Heisenberg is one of the founders of quantum mechanics, and one of the pioneers and intellectual leaders of the Copenhagen interpretation of quantum mechanics. He proposed in two seminal papers in 1925 and 1927, the fundamentals of matrix mechanics (1925) as the first formalism of quantum mechanics, and then the uncertainty relations (1927) as one of the essential components of the Copenhagen interpretation. The purpose of this paper is to formulate Heisenberg's philosophical approaches during the formation of quantum mechanics and its Copenhagen interpretation. The main question of the paper is whether philosophical approaches can be formulated in the development of quantum mechanics through Heisenberg's works? To answer this question, two seminal papers by Heisenberg (1925 and 1927) are examined. The research method of the paper is based on the content analysis of the text (physics) of Heisenberg's papers. The findings of this study show that three crucial principles - observability, correspondence, and analogy-can be formulated from Heisenberg's 1925 paper, which has played a key role in the formation of the fundamentals of matrix mechanics. Moreover, from his 1927 paper, some issues are addressed including interpretation, understanding and classical-quantum relation, the role of experience and measurement, the subject of causality, as well as reality. Finally, it is concluded that through these works of Heisenberg, four philosophical approaches can be formulated including empiricism, Unificationism, indeterminism, and anti-causality, as well as anti-realism, which themselves include other sub-approaches.

Albert Messiah

Filip Grygar

The article focuses on the misleading story of the so-called Copenhagen interpretation of quantum mechanics. The interpretation was allegedly created as unitary or consistent and shared by its founders in 1927 by virtue of the so-called Copenhagen spirit of quantum theory. The paper is based on the role which two leading figures, Niels Bohr and Werner Heisenberg, played in this story. The first part of the article introduces variations of what is considered to be Copenhagen interpretation. The second part reveals that while quantum mechanics had originated in the 1920s, the Copenhagen interpretation was mainly a problematic Heisenbergʼs product of the 1950s. One of his main motivations for the introduction of Copenhagen interpretation was to set up a defence against increasing criticism of the supporters of quantum theory. Since there was no unitary or consistent interpretation of quantum mechanics among members of the so-called Copenhagen school, the last part of the paper focuses on several differences primarily between Bohr and Heisenberg’s interpretation.

Willem M. de Muynck, Guillaume Adenier, Andrei Yu. Khrennikov +3 more

Positive and negative features of the Copenhagen interpretation are discussed. As positive features can be mentioned its pragmatism and its awareness of the crucial role of measurement. However, the main part of the contribution is devoted to the negative features, to wit, its pragmatism (once again), its confounding of preparation and measurement, its classical account of measurement, its completeness claims, the ambiguity of its notion of correspondence, its confused notion of complementarity. It is demonstrated how confusions and paradoxes stemming from the negative features of the Copenhagen interpretation can be dealt with in an amended interpretation, to be referred to as `neo-Copenhagen interpretation', in which the role of the measuring instrument is taken seriously by recognizing the quantum mechanical character of its interaction with the microscopic object. The ensuing necessity of extending the notion of a quantum mechanical observable from the Hermitian operator of the standard formalism to the positive operator-valued measure of a generalized formalism is demonstrated to yield a sound mathematical basis for a transition from the Copenhagen contextualistic-realist interpretation to the neo-Copenhagen empiricist one. Applications to the uncertainty relations and to the Bell inequalities are briefly discussed.