[Paper Review] Is realism compatible with true randomness ?

Nicolas Gisin|arXiv (Cornell University)|Dec 12, 2010

Quantum Mechanics and Applications14 references3 citations

TL;DR

This paper argues that realism and true randomness are fully compatible, proposing that quantum randomness reflects 'propensities'—non-deterministic but law-governed tendencies rooted in preexisting physical properties. It shows that even a single bit of free will deficiency can prevent Bell inequality violations, implying that minimal free will is sufficient for nonlocality tests, and reinterprets quantum nonlocality as a manifestation of genuine creation rather than non-reality.

ABSTRACT

It is argued that realism and true randomness are fully compatible. Realistic true random events are acts of pure creation that obey strict laws, but do not necessarily satisfy Kolmogorov's axioms of probabilities. Realistic true randomness is some sort of nondeterministic force, or propensity of physical systems to manifest such and such properties under such and such conditions. Realistic random events reflect preexisting properties, as required by realism, simply the reflection is not deterministic; still, the preexisting properties determine the propensities of the different possible events. It is argued that deterministic extensions of quantum physics are necessarily incompatible with special relativity. Hence, from today's violations of Bell's inequalities one can conclude that all future physics theories will display true randomness as does quantum physics. It is argued that accepting true randomness and realism leads to new questions with interesting answers, allowing one 1) to study nonlocality in configurations with many independent sources and 2) to bound how much free will is needed for a proper violation of Bell's inequality.

Motivation & Objective

• To resolve the apparent conflict between realism and true randomness in quantum physics.
• To argue that non-deterministic events reflecting preexisting properties (propensities) are compatible with realism.
• To investigate how minimal free will affects the violation of Bell inequalities in nonlocality experiments.
• To demonstrate that even partial free will loss (e.g., one bit) can prevent Bell inequality violations, implying a lower bound on required free will.
• To reframe quantum nonlocality not as a challenge to realism but as evidence of genuine, non-deterministic creation.

Proposed method

• Proposes that true randomness in quantum physics reflects 'propensities'—non-deterministic but law-governed tendencies of physical systems.
• Argues that preexisting physical properties determine these propensities, thus preserving realism without determinism.
• Uses the framework of Bell inequalities to analyze the role of free will in nonlocality experiments.
• Applies the concept of 'lack of free will' as a reduction in input choice (e.g., from 4 to 2 inputs), modeling it as a 1-bit deficiency.
• Analyzes the simulation of quantum correlations under restricted free will, showing that a single bit loss can fully explain all standard two-qubit projective measurements.
• Draws analogies to detection loophole models to illustrate how reduced free will can mimic quantum nonlocality.

Experimental results

Research questions

• RQ1 Can true randomness coexist with realism in quantum physics?
• RQ2 What is the role of preexisting physical properties in determining non-deterministic outcomes?
• RQ3 How much free will is required to observe a violation of a Bell inequality?
• RQ4 Can a lack of free will (e.g., one bit) prevent the observation of quantum nonlocality?
• RQ5 Is quantum nonlocality better understood as a form of genuine creation rather than non-reality?

Key findings

• True randomness and realism are compatible when randomness is interpreted as physical propensity—non-deterministic but law-governed reflection of preexisting properties.
• A single bit of free will deficiency in one party (e.g., Alice) is sufficient to prevent any violation of Bell inequalities with binary outcomes, even for arbitrarily large input alphabets.
• The paper proves that all standard projective measurements on two-qubit maximally entangled states can be simulated if Alice lacks just one bit of free will, regardless of Bob’s free will.
• This result implies a surprising lower bound on free will: physicists must possess at least a minimal degree of free will to perform meaningful Bell tests.
• The violation of Bell inequalities does not imply non-realism; instead, it may reflect the existence of genuine, non-deterministic creation processes.
• The paper reinterprets quantum nonlocality not as a threat to realism but as evidence of a real, non-deterministic process of becoming.