Document Type
Article
Publication Date
2014
Abstract
The status of the quantum state is perhaps the most controversial issue in the foundations of quantum theory. Is it an epistemic state (state of knowledge) or an ontic state (state of reality)? In realist models of quantum theory, the epistemic view asserts that nonorthogonal quantum states correspond to overlapping probability measures over the true ontic states. This naturally accounts for a large number of otherwise puzzling quantum phenomena. For example, the indistinguishability of nonorthogonal states is explained by the fact that the ontic state sometimes lies in the overlap region, in which case there is nothing in reality that could distinguish the two states. For this to work, the amount of overlap of the probability measures should be comparable to the indistinguishability of the quantum states. In this Letter, I exhibit a family of states for which the ratio of these two quantities must be ≤ 2de−cd in Hilbert spaces of dimension d that are divisible by 4. This implies that, for large Hilbert space dimension, the epistemic explanation of indistinguishability becomes implausible at an exponential rate as the Hilbert space dimension increases.
Recommended Citation
Leifer, M.S., 2014. ψ-Epistemic Models are Exponentially Bad at Explaining the Distinguishability of Quantum States. Phys. Rev. Lett. 112, 160404. doi:10.1103/PhysRevLett.112.160404
Peer Reviewed
1
Copyright
American Physical Society
Comments
This article was originally published in Physical Review Letters, volume 112, in 2014. DOI: 10.1103/PhysRevLett.112.160404