Source-linked AI summary
Implications of the Pusey-Barrett-Rudolph quantum no-go theorem
Maximilian Schlosshauer, Arthur Fine
TL;DR
The paper examines which hidden-variables models the PBR theorem constrains and which composite-system assumptions it requires. It characterizes compactness as the weakest needed assumption, constructs evading models, and concludes that the result concerns built-in inefficiencies rather than incorrect Born statistics.
Problem
The paper asks which hidden-variables models and composite-system assumptions are actually targeted by the PBR no-go theorem, and how its implications should be understood.
Source: pp. 1, 3Method
The authors distinguish mixed from segregated models and state-dependent from state-independent response functions, then analyze composite-system assumptions and construct equivalent models that evade PBR.
Source: pp. 1, 3, 4Results
Compactness is identified as sufficient for PBR’s conclusion that state-independent composite models have measurements with built-in inefficiencies, while equivalent models can evade the theorem.
Source: pp. 3–4Takeaways & Limitations
The theorem is not a no-go result for component systems or mixed models generally; its restrictions concern composites and can be compatible with recovering Born probabilities from available outcomes.
Source: p. 4Testing the theorem may be difficult because hidden-variable overlap can be buried in ordinary laboratory inefficiency, so tests may need signatures beyond inefficiency.
Source: p. 4
Abstract
from arXiv · showhide
Pusey, Barrett, and Rudolph introduce a new no-go theorem for hidden-variables models of quantum theory. We make precise the class of models targeted and construct equivalent models that evade the theorem. The theorem requires assumptions for models of composite systems, which we examine, determining "compactness" as the weakest assumption needed. On that basis, we demonstrate results of the Bell-Kochen-Specker theorem. Given compactness and the relevant class of models, the theorem can be seen as showing that some measurements on composite systems must have built-in inefficiencies, complicating its testing.