What are Physical States?

Stephen Boughn

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arXiv · 1903.10348

What are Physical States?

Stephen Boughn

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Abstract

The concept of the physical state of a system is ubiquitous in physics but is usually presented in terms of specific cases. For example, the state of a point particle of mass m is completely characterized by its position and momentum. There is a tendency to consider such states as "real", i.e., as physical properties of a system. This rarely causes problems in classical physics but the notion of real quantum states has contributed mightily to the philosophical conundrums associated with quantum mechanics. The Einstein-Rosen-Podolsky paradox is a prime example. In fact, quantum states are not physical properties of a system but rather subjective descriptions that depend on the information available to a particular observer. This realization goes a long way toward resolving such dilemmas as Schr\"odinger's cat, wave function collapse, quantum non-locality, and parallel universes.

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Stephen Boughn. 2019-03-22. What are Physical States?. https://arxiv.org/abs/1903.10348

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