Price and Wharton have recently suggested that "constrained retrocausal collider bias is the origin of entanglement." In this paper, we argue that their connection across a constrained collider (CCC) for the V-shaped case with the Bell states is not "a mechanism for entanglement," providing a negative answer to the title of arXiv:2406.04571. Rather, CCC should be viewed as a novel approach to the causal modeling of entanglement, providing a perspectival co-causal relationship between the two wings of the experiment that does not violate locality or statistical independence. The key is to accept that quantum mechanics is complete, so the Bell states provide the "mechanism for entanglement" and CCC provides a causal model of entanglement per causal perspectivalism in accord with the different subjective spacetime models of the experiment. When combined into an objective spacetime model of the experiment, the subjective co-causation disappears leaving an objective acausal view of entanglement in accord with the quantum reconstruction program. Essentially, the quantum reconstruction program has rendered quantum mechanics a principle theory based on the observer-independence of Planck's constant h as justified by the relativity principle ("no preferred reference frame" NPRF), exactly as special relativity is a principle theory based on the observer-independence of the speed of light c as justified by the relativity principle. Thus, NPRF + c is an adynamical global constraint on the configuration of worldtubes for the equipment in the experiment while NPRF + h is an adynamical global constraint on the distribution of quantum detection events in that context. Accordingly, CCC then provides a new way to understand causation subjectively per causal perspectivalism in this objectively acausal spacetime model of the experiment.
Price and Wharton have recently suggested that "constrained retrocausal collider bias is the origin of entanglement." In this paper, we argue that their connection across a constrained collider (CCC) for the V-shaped case with the Bell states is not "a mechanism for entanglement," providing a negative answer to the title of arXiv:2406.04571. Rather, CCC should be viewed as a novel approach to the causal modeling of entanglement, providing a perspectival co-causal relationship between the two wings of the experiment that does not violate locality or statistical independence. The key is to accept that quantum mechanics is complete, so the Bell states provide the "mechanism for entanglement" and CCC provides a causal model of entanglement per causal perspectivalism in accord with the different subjective spacetime models of the experiment. When combined into an objective spacetime model of the experiment, the subjective co-causation disappears leaving an objective acausal view of entanglement in accord with the quantum reconstruction program. Essentially, the quantum reconstruction program has rendered quantum mechanics a principle theory based on the observer-independence of Planck's constant h as justified by the relativity principle ("no preferred reference frame" NPRF), exactly as special relativity is a principle theory based on the observer-independence of the speed of light c as justified by the relativity principle. Thus, NPRF + c is an adynamical global constraint on the configuration of worldtubes for the equipment in the experiment while NPRF + h is an adynamical global constraint on the distribution of quantum detection events in that context. Accordingly, CCC then provides a new way to understand causation subjectively per causal perspectivalism in this objectively acausal spacetime model of the experiment.
In this piece, written for a general audience, we propose a mechanism for quantum entanglement. The key ingredient is collider bias. In the language of causal models, a collider is a variable causally influenced by two or more other variables. Conditioning on a collider typically produces non-causal correlations between its contributing causes. This phenomenon can produce associations analogous to Bell correlations, in suitable post-selected ensembles. Such collider artefacts may become real connections, resembling causality, if a collider is 'constrained' (e.g., by a future boundary condition). We consider the time-reversed analogues of these points in the context of retrocausal models of QM. Retrocausality yields a collider at the source of an EPR-Bell particle pair, and in this case constraint of the collider is possible by normal methods of experimental preparation. It follows that connections resembling causality may emerge across such colliders, from one branch of the experiment to the other. Our hypothesis is that this constrained retrocausal collider bias is the origin of entanglement. This piece is based on a suggestion first made in arXiv:2101.05370v4 [quant-ph], and is an ancestor of an essay now published online in Aeon magazine [Price & Wharton 2023a]. In an updated version of the argument in arXiv:2309.10969 [quant-ph] we (i) demonstrate its application in a real Bell experiment; and (ii) show that we can do without an explicit postulate of retrocausality
We propose a mechanism for quantum entanglement. The key ingredient is the familiar statistical phenomenon of collider bias, or Berkson's bias. In the language of causal models a collider is a variable causally influenced by two or more other variables. Conditioning on a collider typically produces non-causal associations between its contributing causes, even if they are actually independent. It is easy to show that this phenomenon can produce associations analogous to Bell correlations, in suitable post-selected ensembles. It is also straightforward that such collider artefacts may become real connections, resembling causality, if a collider is 'constrained' (e.g., by a future boundary condition). We consider the time-reversed analogues of these points in the context of retrocausal models of QM. Retrocausality yields a collider at the source of an EPR-Bell particle pair, and in this case constraint of the collider is possible by normal methods of experimental preparation. It follows that connections resembling causality may be expected to emerge across such colliders, from one branch of the experiment to the other. Our hypothesis is that this constrained retrocausal collider bias is the origin of entanglement. The piece is written for a general audience, and is based on a suggestion first made in arXiv:2101.05370 [quant-ph].
In this piece, written for a general audience, we propose a mechanism for quantum entanglement. The key ingredient is the familiar statistical phenomenon of collider bias, or Berkson's bias. In the language of causal models a collider is a variable causally influenced by two or more other variables. Conditioning on a collider typically produces non-causal associations between its contributing causes, even if they are actually independent. It is easy to show that this phenomenon can produce associations analogous to Bell correlations, in suitable post-selected ensembles. It is also straightforward that such collider artefacts may become real connections, resembling causality, if a collider is 'constrained' (e.g., by a future boundary condition). We consider the time-reversed analogues of these points in the context of retrocausal models of QM. Retrocausality yields a collider at the source of an EPR-Bell particle pair, and in this case constraint of the collider is possible by normal methods of experimental preparation. It follows that connections resembling causality may be expected to emerge across such colliders, from one branch of the experiment to the other. Our hypothesis is that this constrained retrocausal collider bias is the origin of entanglement. The piece is based on a suggestion first made in arXiv:2101.05370 [quant-ph].
Many in quantum foundations seek a principle explanation of Bell state entanglement. While reconstructions of quantum mechanics (QM) have been produced, the community does not find them compelling. Herein we offer a principle explanation for Bell state entanglement, i.e., conservation per no preferred reference frame (NPRF), such that NPRF unifies Bell state entanglement with length contraction and time dilation from special relativity (SR). What makes this a principle explanation is that it's grounded directly in phenomenology, it is an adynamical and acausal explanation that involves adynamical global constraints as opposed to dynamical laws or causal mechanisms, and it's unifying with respect to QM and SR.
In this piece, written for a general audience, we propose a mechanism for quantum entanglement. The key ingredient is the familiar statistical phenomenon of collider bias, or Berkson's bias. In the language of causal models, a collider is a variable causally influenced by two or more other variables. Conditioning on a collider typically produces non-causal associations between its contributing causes, even if they are actually independent. It is easy to show that this phenomenon can produce associations analogous to Bell correlations, in suitable post-selected ensembles. It is also straightforward that such collider artefacts may become real connections, resembling causality, if a collider is 'constrained' (e.g., by a future boundary condition). We consider the time-reversed analogues of these points in the context of retrocausal models of QM. Retrocausality yields a collider at the source of an EPR-Bell particle pair, and in this case constraint of the collider is possible by normal methods of experimental preparation. It follows that connections resembling causality may be expected to emerge across such colliders, from one branch of the experiment to the other. Our hypothesis is that this constrained retrocausal collider bias is the origin of entanglement. The piece is based on a suggestion we first made in arXiv:2101.05370v4 [quant-ph].
Many in quantum foundations seek a principle explanation of Bell state entanglement. While reconstructions of quantum mechanics (QM) have been produced, the community does not find them compelling. Herein we offer a principle explanation for Bell state entanglement, i.e., conservation per no preferred reference frame (NPRF), such that NPRF unifies Bell state entanglement with length contraction and time dilation from special relativity (SR). What makes this a principle explanation is that it's grounded directly in phenomenology, it is an adynamical and acausal explanation that involves adynamical global constraints as opposed to dynamical laws or causal mechanisms, and it's unifying with respect to QM and SR.