Book Reviewed: The Meaning of the Wave Function: In Search of the Ontology of Quantum Mechanics by Shan Gao

Physics & Philosophy: Quantum reality and the nature of wave function

This is about the physics and philosophy of the wave function that holds key to understanding quantum reality. But the discussions are narrowly focused, and reckless in blatant disregard for a balanced discussion. The author is on a mission to promote his ideas instead of an all-around discussion of wave functions. On the brighter side, there are very few equations and little mathematics. So, the reading is straightforward and easy to assimilate the discussions and the subject matter. This is intended for general readers interested in physics and philosophy of quantum reality, and the author’s writing skills makes reading easy.

In quantum physics, a wave function is a variable quantity that mathematically describes the wave characteristics of a particle. The value of the wave function of this particle, at a given point of space and time is related to the likelihood (probability) of that particle’s being there at a time. But it is the square of the wave function, Ψ2 that acquires the physical significance of existence.

The author argues that the wave function in quantum mechanics is real, and it represents the state of random discontinuous motion (RDM) of particles in three-dimensional space. He posits a picture of quantum ontology that accounts for our definite experience, but that requires that the quantum dynamics be revised to include a stochastic nonlinear evolution term resulting from the RDM of particles. Therefore, it follows that the wave function is real, and it represents a physical property of a single quantum system. This new interpretation represents an alternative to wave function realism interpretations.

Shan Gao ignores other approaches to wave functions except Realism, where the wave function represents something objective and mind independent reality. The realism approach may be grouped into three categories: ontological interpretations (analysis of being), nomological interpretations (on par with laws of nature), and the sui generis interpretation; here the wave function is neither ontological nor nomological, but it is distinct and unique. But Gao considers only the ontological interpretation in which the wave function is interpreted as part a of the fundamental material ontology, on par with particles, fields, space-time events or properties, which are the kind of microscopic/subatomic materials that make up macroscopic/molecular materials such as books and rocks. For a wave function to be nomological, it must be to be like a fundamental law in which one might expect it to be time independent.

In quantum mechanics, the fundamental physical space is high-dimensional. In configuration space fundamentalism, it is ((10exp80) dimensions. But it is possibly infinite in Hilbert space fundamentalism. Considering just three-dimensional space in the author’s interpretation calls for some discussions. For a clearheaded discussion of wave function physics, I recommend reading a recent paper by Eddy Chen. This is a lucid and easy to understand presentation of the topic (Realism about the Wave Function, Forthcoming in Philosophy Compass, June 12, 2019; arXiv:1810.07010 [quant-ph].