Talk: Simon Friederich (Groningen)

Title:

Quantization as the root of the measurement problem – and as the key to its solution

Abstract:

I propose a new perspective on quantization, centred around the idea that “not giving rise to a measurement problem” can be turned into a fruitful criterion for the choice of quantization scheme. Notably, I suggest to combine assuming that a quantum system has a sharp phase space location, and thereby avoiding the measurement problem, with regarding its classical dynamical variables as the correct ones. The self-adjoint Hilbert space operators assigned to these by quantization merely “represent” them, for the purposes of calculation. An immediate attraction of this idea is that it makes the Kochen-Specker theorem obsolete because quantization, in general, does not leave algebraic relations invariant, thereby undermining the intuitive appeal of Kochen-Specker non-contextuality.

Concretely, the idea that a quantization scheme Q: A→Â should not give rise to a measurement problem can be encoded in the criterion that, for any (“classical”) dynamical variable A, its quantum expectation value Tr(ρ Â) should be interpretable as a weighted phase space integral of the “classical” A, with a suitable probability distribution P. It turns out that, in ordinary quantum mechanics, such an interpretation is viable for Anti-Wick quantization. Here the role of the phase space probability distribution P on phase space is played by the Husimi-function Q. Anti-Wick quantization can be seen as a special case of two more widely generalizable approaches to quantization: “Berezin-Toeplitz quantization” and “coherent state quantization.” I conclude that investigating the applicability and empirical viability of these approaches is a promising avenue for turning “solving the measurement problem” into a criterion that may stimulate future progress in physics.