Project A1
The formation and development
of the concept of virtual particles

The formation and development of the concept of virtual particles



This project investigates the concept of a virtual particle from the viewpoint of the history and philosophy of science (“integrated HPS”). This concept is an integral part of modern physics, mainly since it provides a means to describe and interpret complex quantum physical processes in comparatively simple terms. Despite its wide use, the notion of a virtual particle appears not to be clearly defined. The present project traces the origins of the concept and follows its evolution through time. Phase 1 investigated systematically the reasons for the introduction of the concept in quantum mechanics and early quantum field theory (QFT). Phase 2 will focus on the further development of the concept in the context of QFT, S-matrix theory, and the Standard Model. In this phase, we also aim to explain the genesis of today’s diverse uses of the term and, taking into account the results from the previous phase, to further our general understanding of concept formation in the physical sciences.

Deutsche Version


Principal Investigators:
Robert Harlander
Adrian Wüthrich

Principal Collaborator:
Friedrich Steinle

Postdoctoral Researcher:
Dr. Jean-Philippe Martinez



Student assistant:
Michael Zichert

Previous Members:
Daniel Mitchell (former postdoctoral researcher)
Markus Ehberger (former doctoral researcher)


Cooperation Partners:
Volker Remmert



Relevant Publications

Robert Harlander, "Feynman diagrams: From complexity to simplicity and back”, Synthese 199 (2021) 5-6, 15087-15111

Ehberger, M. (forthcoming). I’m Not There or: Was the Virtual Particle Ever Born? In Forstner, C., Walker, M., and Hoffmann, D. (eds.), Proceedings to the workshop “Biographies in the History of Physics: Actors, Institutions and Objects", Bad Honnef, 22.–25. May 2018, Springer.

Wüthrich, A. (2017). Discovering and “Rediscovering" the W Boson. Annalen der Physik, 529(5).

Wüthrich, A. (2018). The Exigencies of War and the Stink of a Theoretical Problem: Understanding the Genesis of Feynman’s Quantum Electrodynamics as Mechanistic Modelling at Different Levels. Perspectives on Science, 26(4):501–520.