Is a system's wave function in one-to-one correspondence with its elements of reality?

TL;DR

This paper argues that, under the assumption of free choice of measurement settings, a system's wave function uniquely corresponds to its elements of reality, challenging subjective interpretations of quantum states.

Contribution

It proves that the wave function is in one-to-one correspondence with elements of reality assuming free measurement choices, ruling out subjective interpretations.

Findings

Wave function uniquely corresponds to elements of reality.

Subjective interpretation of the wave function is incompatible with free measurement choices.

Supports an objective view of quantum states.

Abstract

Although quantum mechanics is one of our most successful physical theories, there has been a long-standing debate about the interpretation of the wave function---the central object of the theory. Two prominent views are that (i) it corresponds to an element of reality, i.e. an objective attribute that exists before measurement, and (ii) it is a subjective state of knowledge about some underlying reality. A recent result [Pusey et al. arXiv:1111.3328] has placed the subjective interpretation into doubt, showing that it would contradict certain physically plausible assumptions, in particular that multiple systems can be prepared such that their elements of reality are uncorrelated. Here we show, based only on the assumption that measurement settings can be chosen freely, that a system's wave function is in one-to-one correspondence with its elements of reality. This also eliminates the possibility that it can be interpreted subjectively.