Editor, Einstein Papers Project, Boston (1995–2000);
Assistant professor, philosophy, Boston University (1997–2000);
Assistant professor (2000–2005), history of science, University of Minnesota.
Associate professor (2005– ), history of science, University of Minnesota.
Named an APS Fellow (2012) for his "path-breaking contributions to the history of early twentieth-century physics."
I work on the history of relativity theory (special and general) and quantum theory.
In the history of general relativity, I have been especially interested in Einstein's heroic but ultimately unsuccessful struggle to find a true theory of relativity. My work for the Einstein Papers Project editing all material on general relativity in Vols. 7 and 8 of Einstein's Collected Papers has put me in an ideal position to tell this tale. The moral of my story is that Einstein's struggle was not in vain. Along the way, he achieved important results that are still with us today: a new theory of gravity improving greatly on Newton's and opening up entirely new fields such as relativistic cosmology, gravitational waves, and gravitational lensing. A line from "Love minus zero/no limit," a song by Minnesota's greatest son, Bob Dylan, provided the perfect title for a paper about this story that I wrote for the Cambridge Companion to Einstein of which I am one of the two editors: "'No success like failure …': Einstein's quest for general relativity, 1907-1920."
In the history of special relativity, my main interest is in the transition from the electromagnetic mechanics of Max Abraham to the relativistic continuum mechanics of Max Laue. Work in the history of special relativity typically focuses on the transformations of our concepts of space and time, treating such well-known phenomena as the slowing-down of moving clocks and the universal contraction of moving objects. The profound implications of special relativity for mechanics usually go unaddressed, even though the theory's most famous formula, E = mc2, is part of relativistic mechanics. Classical mechanics lacked the resources to deal with systems involving the interaction of matter and electromagnetic fields, an area of particular interest in the early 1900s. Classical theory led to such baffling and counter-intuitive predictions that electric forces would move a charged body into a position in which its energy is at a maximum rather than at a minimum; or that charged bodies carry momentum that is at right angles with their direction of motion. Many of these puzzles arose from the experiments by Trouton and Noble, analyzed in my dissertation. They are easily solved once classical mechanics is replaced by relativistic mechanics. Even though Einstein identified this transition in 1912 as the watershed advance in relativity theory, it has never been systematically discussed in the extensive literature on the history of special relativity.
In the history of quantum mechanics, I've been working on a series of papers (together with Tony Duncan, a high-energy theorist at the University of Pittsburgh) on the origins of matrix mechanics in dispersion theory and its further development, especially through the work of Pascual Jordan.
Anthony Duncan and Michel Janssen, On the Verge of Umdeutung in Minnesota: Van Vleck and the Correspondence Principle., Archive for History of Exact Sciences 61 (2007): 553–624, 625–671 [abstract]
Michel Janssen, Drawing the Line between Kinematics and Dynamics in Special Relativity, Studies in History and Philosophy of Modern Physics 40 (2009) 26–52 [abstract]
Michel Janssen and Matthew Mecklenburg, From Classical to Relativistic Mechanics: Electromagnetic Models of the Electron., Interactions: Mathematics, Physics and Philosophy (2007)
Michel Janssen, Of Pots and Holes: Einstein’s Bumpy Road to General Relativity., Annalen der Physik 14, Supplement (2005)
Anthony Duncan and Michel Janssen, Pascual Jordan’s Resolution of the Conundrum of the Wave-Particle Duality of Light, Studies in History and Philosophy of Modern Physics 39 (2008): 634–666 [abstract]
Michel Janssen, What Did Einstein Know and When Did He Know It? A Besso Memo Dated August 1913, Jürgen Renn (Ed.), Einstein’s Zurich Notebook. Vol. 2, Commentary and Essays. Dordrecht: Springer, 2007.
Michel Janssen and Jürgen Renn, Untying the Knot: How Einstein Found His Way Back to Field Equations Discarded in the Zurich Notebook, Jürgen Renn (Ed.), Einstein’s Zurich Notebook. Vol. 2, Commentary and Essays. Dordrecht: Springer, 2007.
Michel Janssen, The Trouton Experiment, E = mc2, and a Slice of Minkowski Space-Time, In: Abhay Ashtekar et al. (ed.), Revisiting the Foundations of Relativistic Physics: Festschrift in Honor of John Stachel. Dordrecht: Kluwer, 2003. Pp. 27–54.
Michel Janssen, COI Stories: Explanation and Evidence in the History of Science, Perspectives on Science. 10 (2002): 457522. [abstract]
Michel Janssen, Reconsidering a Scientific Revolution: the Case of Lorentz versus Einstein, Physics in Perspective 4 (2002): 421–446. [abstract]