Source-linked AI summary
Distinct Quantum States Can Be Compatible with a Single State of Reality
Peter G. Lewis, David Jennings, Jonathan Barrett, Terry Rudolph
TL;DR
The paper asks whether distinct quantum states can correspond to overlapping distributions over underlying physical states, challenging a no-go result that assumes preparation independence. By explicitly constructing such models while retaining quantum predictions, it shows that ruling out ψ-epistemic models requires additional assumptions, although the constructions are contrived and do not meet the stronger overlap condition for every pair of non-orthogonal states.
Problem
The paper asks whether quantum states can fail to uniquely determine underlying physical states, despite a no-go theorem based on preparation independence.
Source: p. 1Method
The authors construct ontological models in which measurement outcomes depend on underlying states while distinct quantum-state distributions overlap.
Source: pp. 2–3Results
Explicit constructions reproduce all quantum predictions while allowing ψ-epistemic overlap when preparation independence is abandoned.
Source: pp. 1, 4Takeaways & Limitations
The result shows that any no-go theorem excluding ψ-epistemic models must use non-trivial assumptions beyond those required for a well-formed ontological model.
Source: p. 1The models are contrived and do not have non-zero overlap for every pair of non-orthogonal quantum states.
Source: p. 4
Abstract
from arXiv · showhide
Perhaps the quantum state represents information about reality, and not reality directly. Wave function collapse is then possibly no more mysterious than a Bayesian update of a probability distribution given new data. We consider models for quantum systems with measurement outcomes determined by an underlying physical state of the system but where several quantum states are consistent with a single underlying state---i.e., probability distributions for distinct quantum states overlap. Significantly, we demonstrate by example that additional assumptions are always necessary to rule out such a model.