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Quantum Entanglement

Notes

Quantum Entanglement

One-line summary: Two particles prepared together stay correlated at any distance — the universe treats them as one system, with space and time between them seemingly irrelevant.

The insight

Per michelle-thaller, two electrons that shared an orbital must have opposite spins; separate them by any distance and they remain a single quantum system, so changing one's spin is reflected in the other "immediately... regardless of the distance." Einstein disliked this ("spooky action at a distance"); experiments from the mid-1990s confirmed it (Chinese experiments have run entanglement up to the space station and back). The deep claim Thaller draws out: the universe says "the space and time between them doesn't matter. They're the same system."

Evidence

Contradictions / tensions

The "many-worlds" reading of fast quantum computation and of interferometry (the same photon measured in many places at once) is explicitly one interpretation among several. Thaller notes "many interferometrists don't interpret it that way" — they say only that space and time don't behave classically at quantum scales. The thread should not treat many-worlds as settled.

Open questions

  • Could a civilization harness entanglement for communication/travel without moving through space? Resolved (2026-05-30 autoresearch): No — the no-communication-theorem proves entanglement cannot transmit usable information faster than light. The JRE riff on this (via the Three-Body Problem "sophons") was conjecture and is contradicted by established physics. Entanglement gives correlations, not a signal.
  • Which interpretation of quantum mechanics underlies entanglement (many-worlds, collapse, …)? Bell tests constrain but don't select one — see bells-theorem-and-local-realism.
  • what-is-time

Related

Referenced by