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Physics

Unitary Evolution Core Concepts

Quick fact

Unitary evolution is so perfectly reversible that it can 'undo' itself: if you reverse the direction of time in the Schrödinger equation, the system returns to its original state without losing information.

Why this is interesting

You've probably seen a spinning coin—when it's upright, it's like a quantum superposition of heads and tails, but as it evolves, something subtle and perfectly reversible is happening. What rule governs this quantum dance?