Quantum t-designs: t-wise independence in the quantum world

独立性公设对物理学的若干启示

Some Implications of the Independence Postulate for Physics

本文论证多世界理论与构造者理论均同独立性公设冲突：前者经有限电子自旋测量会产生含禁用序列的正概率分支，后者的反事实二元分类则难以描述禁用序列的发现或创造。

Strong Quantum Darwinism and Strong Independence is equivalent to Spectrum Broadcast Structure

How the objective everyday world emerges from the underlying quantum behaviour of its microscopic constituents is an open question at the heart of the foundations of quantum mechanics. Quantum Darwinism and spectrum broadcast structure are two different frameworks providing key insight into this question. Recent works, however, indicate these two frameworks can lead to conflicting predictions on the objectivity of the state of a system interacting with an environment. Here we provide a resolution to this issue by defining strong quantum Darwinism and proving that it is equivalent to spectrum b…

What does the world look like according to superdeterminism?

The violation of Bell inequalities seems to establish an important fact about the world: that it is non-local. However, this result relies on the assumption of the statistical independence of the measurement settings with respect to potential past events that might have determined them. Superdeterminism refers to the view that a local, and determinist, account of Bell inequalities violations is possible, by rejecting this assumption of statistical independence. We examine and clarify various problems with superdeterminism, looking in particular at its consequences on the nature of scientific l…

Subsystems and Independence in Relativistic Microscopic Physics

The analyzability of the universe into subsystems requires a concept of the "independence" of the subsystems, of which the relativistic quantum world supports many distinct notions which either coincide or are trivial in the classical setting. The multitude of such notions and the complex relations between them will only be adumbrated here. The emphasis of the discussion is placed upon the warrant for and the consequences of a particular notion of subsystem independence, which, it is proposed, should be viewed as primary and, it is argued, provides a reasonable framework within which to sensib…

Peaceful Coexistence: Examining Kent's Relativistic Solution to the Quantum Measurement Problem

Can there be `peaceful coexistence' between quantum theory and special relativity? Thirty years ago, Shimony hoped that isolating the culprit (i.e. the false assumption) in proofs of Bell inequalities as Outcome Independence would secure such peaceful coexistence: or, if not secure it, at least show a way---maybe the best or only way---to secure it. In this paper, I begin by being sceptical of Shimony's approach, urging that we need a relativistic solution to the quantum measurement problem (Section 2). Then I analyse Outcome Independence in Kent's realist one-world Lorentz-invariant interpret…