Can different quantum state vectors correspond to the same physical state? An experimental test

TL;DR

This paper reports an experimental test using trapped ions to determine whether different quantum state vectors can correspond to the same physical state, ultimately confirming quantum theory and ruling out certain interpretations.

Contribution

The study provides an experimental validation of quantum theory against models where the wave function is non-physical, using a novel trapped ion setup.

Findings

Results confirm quantum theory within experimental error.

Certain models linking wave function to knowledge are ruled out.

Supports the view that quantum states correspond to physical states.

Abstract

A century on from the development of quantum theory, the interpretation of a quantum state is still discussed. If a physicist claims to have produced a system with a particular wave function, does this represent directly a physical wave of some kind, or is the wave function merely a summary of knowledge, or information, about the system? A recent no-go theorem shows that models in which the wave function is not physical, but corresponds only to an experimenter's information about a hypothetical real state of the system, must make different predictions from quantum theory when a certain test is carried out. Here we report on an experimental implementation using trapped ions. Within experimental error, the results confirm quantum theory. We analyse which kinds of theories are ruled out.