UCG research group: The Groningen Philosophy of Physics Group

The Groningen Philosophy of Physics Group is hosted by the UCG. Our work is broadly focused on, but not limited to, understanding the nature of probability, causality, spacetime and symmetry. Currently, we are investigating two exciting research projects on the quantum measurement problem and explanations of the arrow of time. Our group also has close connections with the Faculty of Philosophy and the Faculty of Science and Engineering.

Two themes were are working on, corresponding to the two research projects above, are: Quantum foundations, quantization, and causality (Simon Friederich, Isa Kooiman, Mritunjay Tyagi) and Symmetries and the arrow of time (Sean Gryb, Simon Friederich).

Quantum foundations, quantization, and causality (Simon Friederich, Isa Kooiman, Mritunjay Tyagi).

As Simon Friederich explains in his video for University of the Netherlands, the empirical success of quantum theory is profoundly puzzling. Supported by Simon Friederich’s VIDI grant “Saving Reality with Exotic Causality” we try to develop a compelling account of quantum theory as describing a single objective reality using a reconsideration of quantization: the procedure of going from a classical to a quantum theory. In particular, we focus on coherent state quantization and the prospects for interpreting the Husimi function on phase space as a proper probability density. Quantum theory predicts correlations between distant events for which there is no obvious causal explanation. To account for this “non-locality”, any empirically viable approach may have to embrace some kind of “exotic” causality, for instance causation backwards in time. We are currently figuring out what this exotic causality must be like and whether it’s acceptable or problematic.

Symmetries and the arrow of time (Sean Gryb, Simon Friederich)

The problem of the arrow of time arises from the observation that almost all processes that we encounter in science and in our everyday lives are strikingly asymmetric in time, whereas the fundamental laws of our best scientific theories are essentially time-symmetric. A popular solution to this problem is to postulate a very special state for the early universe, introducing a radical asymmetry in time that seeds all others. This solution, however, presupposes a notion of “specialness” for states of the universe. Our work on this theme questions this notion on new grounds. In particular, we argue that it treats as distinct states that correspond to a simple rescaling of all the distances in the universe. We then venture to show that the most important time asymmetries we see in our universe can be explained if we adapt the notion of specialness of states to be compatible with the claim that the absolute size of the universe is of no empirical significance. This suggests a new kind of explanation of the arrow of time can be obtained by making the right “counting” of physical states. Sean Gryb’s previous work on this theme was supported by a PhD grant from the Young Academy Groningen (YAG).

Group members

• Simon Friederich
• Sean Gryb
• Isa Kooiman
• Mritunjay Tyagi

Affiliate members

• Leah Henderson (Professor of Philosophy, RUG)
• Jan-Willem Romeijn (Professor of Philosophy of Science, RUG)

GPPG colloquia semester 1 2024-2025

Speakers and dates can be found here.

To receive updates about the GPPG colloquia, please send an email to i.a.kooiman rug.nl to be added to the mailing list.