Experimental refutation of a class of ψ-epistemic models

Abstract

The quantum state is a mathematical object used to determine the outcome probabilities of measurements on physical systems. Its fundamental nature has been the subject of discussions since the origin of the theory: is it ontic, that is, does it correspond to a real property of the physical system? Or is it epistemic, that is, does it merely represent our knowledge about the system? Recent advances in the foundations of quantum theory show that epistemic models that obey a simple continuity condition are in conflict with quantum theory already at the level of a single system. Here we report an experimental test of continuous epistemic models using high-dimensional attenuated coherent states of light traveling in an optical fibre. Due to non-ideal state preparation (of coherent states with imperfectly known phase) and non-ideal measurements (arising from losses and inefficient detection), this experiment only tests epistemic models that satisfy additional constraints which we discuss in detail. Our experimental results are in agreement with the predictions of quantum theory and provide constraints on a class of ψ-epistemic models.

11 pages, 5 figures. v2: minor changes to "Discussion" section and to figures

References in corpus (4)

• Are quantum states real?
• Implications of the Pusey-Barrett-Rudolph quantum no-go theorem
• Maximally epistemic interpretations of the quantum state and contextuality
• No-go theorems for ψ-epistemic models based on a continuity assumption

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• Is the quantum state real? An extended review of $\psi$-ontology theorems
• Measurements on the reality of the wavefunction
• Quantum Theory and Determinism
• Can different quantum state vectors correspond to the same physical state? An experimental test
• Detection efficiency loophole in Pusey-Barrett-Rudolph theorem
• Not-Post-Peierls compatibility under noisy channels