In a recent work, it was shown by one of us (EGC) that Bell-Kochen-Specker inequality violations in phenomena satisfying the no-disturbance condition (a generalisation of the no-signalling condition) cannot in general be explained with a faithful classical causal model---that is, a classical causal model that satisfies the assumption of $\textit{no fine-tuning}$. The proof of that claim however was restricted to Bell scenarios involving 2 parties or Kochen-Specker-contextuality scenarios involving 2 measurements per context. Here we show that the result holds in the general case of arbitrary numbers of parties or measurements per context; it is not an artefact of the simplest scenarios. This result unifies, in full generality, Bell nonlocality and Kochen-Specker contextuality as violations of a fundamental principle of classical causality. We identify, however, an implicit assumption in the former proof, making it explicit here: that certain operational symmetries of the phenomenon are reflected in the model, rather than requiring fine-tuned choices of model parameters. This clarifies a subtle but important distinction between Bell nonlocality and Kochen-Specker contextuality.

中文翻译：

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经典因果模型无法在任意场景中忠实地解释 Bell 非定域性或 Kochen-Specker 上下文

在最近的一项工作中，我们中的一个人 (EGC) 表明，在满足无干扰条件（无信号条件的概括）的现象中违反 Bell-Kochen-Specker 不等式通常不能用忠实的经典解释因果模型---即满足$\textit{无微调}$假设的经典因果模型。然而，该声明的证据仅限于涉及 2 方的 Bell 场景或涉及每个上下文 2 次测量的 Kochen-Specker-contextuality 场景。在这里，我们表明结果适用于每个上下文任意数量的参与方或测量的一般情况；它不是最简单场景的人工制品。这个结果完全统一了 Bell 非定域性和 Kochen-Specker 语境，因为它违反了经典因果关系的基本原则。然而，我们在前一个证明中确定了一个隐含的假设，在这里明确表示：该现象的某些操作对称性反映在模型中，而不是需要对模型参数进行微调选择。这澄清了 Bell 非定域性和 Kochen-Specker 上下文之间微妙但重要的区别。