History and Foundations of Quantum Physics

Webpage of the Project.

The quantum revolution emerges from a series of crises of the classical mechanical worldview from the late 19th century to the 1920s. These crises were caused in part by conflicts between theoretical expectations and experimental results, but also importantly by the difficulty of integrating recently established physical theories such as electrodynamics and thermodynamics into the mechanical worldview. Similar to the case of relativity theory, conflicts between theories necessitated a reorganization and re-evaluation of controversial concepts.

Central to this process of re-evaluation was not only a large amount of uncontroversial empirical knowledge accumulated over a long period of time but also the persistence of certain theoretical structures and methods. Theoretical physicists were therefore confronted with critical decisions about which concepts and theoretical structures could be maintained in the emerging theory and could thus serve as a guide for the development of the theory. As in the case of relativity, it turned out that it was often high-level and abstract structures that survived, although frequently with a new physical interpretation.

Differently from the case of relativity, a consensus about the physical reinterpretation of the abstract structures was not easily attained. Famous dissenters, such as Einstein and Schrödinger, while accepting the new theoretical structure, disagreed about its meaning and its connection to the traditional mechanical worldview. Later on, the establishment of quantum field theory, including the unification with the theory of relativity, has turned out to be at odds with the traditional demands on an interpreted physical theory. These disagreements have persisted up to this day, even though quantum mechanics by all counts is a highly successful predictive theory.

The research project on the history and foundations of quantum physics began work in October of 2006 (Christoph Lehner, Jürgen Renn). It is a joint initiative with the Theory Department of the Fritz Haber Institute and has been funded for five years by the Strategic Innovation Fund of the President of the MPG. The project attempts to arrive at a deeper understanding of the genesis and the development of quantum physics, using the tools of historical epistemology that have been developed in Department I over the last years. The project thus focuses on the long-term history of the process of theory change, stressing the continuity of methods and structures. The experience in writing the history of relativity has demonstrated the strength of this method: It leads to results that have been outside the view of approaches limiting themselves to an account of historical developments narrower in a temporal and contextual sense.

Unlike the relativity revolution, the development of quantum physics was a communal effort whose nature cannot be captured by a biographical approach that focuses upon a few central figures: careful attention must be paid to the broader community of researchers and to the network that allowed them to achieve what no single researcher could do alone. Work in this direction draws upon extensive archival records of correspondence, manuscripts, and notebooks that are investigated and made accessible in an electronic form to other researchers worldwide.

Another important element of the project is the focus on mathematical arguments in the primary source material, a topic not much dealt with in the existing literature. For this aim, the project is conceived as a close collaboration of a large and varied group of historians and philosophers of science as well as working physicists exchanging ideas and viewpoints through frequent meetings (dedicated conferences, workshops and reading groups).

Finally, the history of quantum physics cannot be understood without an appreciation of the radical conceptual changes that it brought. Debates about interpretation played a central role in the development of quantum physics. Therefore, the project investigates the history of the interpretation of quantum mechanics not as a separate “philosophical” subject but as part of a wider debate in physics.

The project aims at fostering the study of the history of quantum physics by facilitating the exchanges between physicists and historians, but also by drawing new scholars into the field through graduate and postdoc fellowships. In addition, one of the main tasks of the project is the maintaining of an electronic infrastructure within the ECHO environment for the publication of primary sources, archival material as well as results of ongoing research by members of the network.

As the central publication of the project, a working group volume in preparation describes the development of quantum mechanics as a long-term process of theory change (Christoph Lehner, Christian Joas, and Jürgen Renn). It emphasizes the continuity of scientific methods and structures through the fundamental changes in the mechanical world picture since the 19th century. This book bundles the individual research programs of the members of the group into a coherent whole, at the same time achieving a legible survey of the development of quantum mechanics, and filling a void between thematically focused technical accounts and popular presentations that do not represent the current historical state of the art. It is being written in close collaboration by all the members of the project, who meet every week for presentations and discussions. In close connection with the working group volume, two edited volumes are also in preparation: One volume (Giuseppe Castagnetti, Michael Eckert, Hubert Goenner, Dieter Hoffmann, Alexei Kojevniknov, Jürgen Renn, Arne Schirrmacher) addresses the role of scientific institutions in the development of quantum theory and comprises, e.g., case studies on the Kaiser Wilhelm Institutes of Physics and Physical Chemistry and the Physikalisch-Technische Reichsanstalt in Berlin, the Sommerfeld school in Munich, Bohr’s institute in Copenhagen, and Göttingen University. The second volume (Massimiliano Badino, James Navarro) analyzes early textbooks of quantum theory and their role in establishing and promoting the theory. For both edited volumes, workshops with the external contributors were organized in 2009. Contributions to the textbook volume were presented in two special sessions at the 2009 HSS meeting in Phoenix, USA.

Besides a biweekly reading group for physicists and historians from local institutions, and a colloquium with invited speakers, a series of conferences was launched by the project in 2007 to strengthen the international network of researchers working in the history of quantum physics. The second conference in this series took place in Utrecht in July 2008. Its proceedings were published as a special issue of Studies in History and Philosophy of Modern Physics (2008, 40: 4). A satellite meeting of the project took place in May 2008 at the University of Sidney. The project also contributed a session entitled "Quantum Physics at the Crossroads" to the 2008 Three Societies Meeting in Oxford, and was featured in a special session “Eighty years of quantum mechanics. A new international project” at the April 2008 meeting of the American Physical Society.

The project contributed the texts for the exhibition “Max Planck: Revolutionär wider Willen” organized by the Max Planck Society at the Deutsches Technik Museum in honor of the 150th birthday of Max Planck. These texts formed the basis for a special issue of Spektrum der Wissenschaft (Biographie). Planck’s birthday was also the occasion for a symposium, organized by the project, of the History of Physics Division of the Deutsche Physikalische Gesellschaft in February 2008 in Berlin. The proceedings of this meeting were published in an edited volume entitled “Max Planck und die moderne Physik” (Dieter Hoffmann).