Simple

The Quantum Coin: Bohr & von Neumann's Solution ⚡ экспресс

Original: "There is No Quantum World"
· Jeffrey Bub
arXiv:2512.18400 · 2025-12-20 · CC BY · ⏱ 1 min · Quantum Physics
A new perspective on measurement blends Bohr's and von Neumann's ideas, showing that the complexity of the apparatus itself eliminates quantum uncertainty.
Abstract

Quantum mechanics often seems strange: particles behave unpredictably until we look at them. The author proposes an updated version of Bohr's idea, where the classical world is like a TV screen—without it, the picture can't be seen. This work shows how mathematics can reconcile the quantum and everyday worlds. Why does reality require an observer?

Links in the knowledge graph 1

A quantum particle—an inhabitant of the elementary particle world—resembles a coin spinning in the air: neither heads nor tails, but a blend of possibilities. Yet when it lands on the table, the outcome becomes definite. What serves as the table in a measurement?

Niels Bohr insisted: the measuring device is part of the classical world, and cannot be described in quantum language. Measurement doesn't destroy the particle; it links it to our familiar surroundings.

The mathematician von Neumann showed that if the device is infinitely complex, its collective behavior inexorably squeezes a definite value out of the particle—much like how disorder inevitably grows in a closed system. The new work fuses Bohr's views with this mathematics: classical concepts are not a choice, but a necessity. The measurement problem vanishes. An unexpected twist: the same logic applies to black holes—there, quantum uncertainty hides behind the horizon, just like the faces of a spinning coin.

🎯 Von Neumann, who invented computer architecture, also brought his love for infinite systems to quantum mechanics: his measurement mathematics echoes the processing of crisp bits from quantum noise.

Scientists
Stephen HawkingJacob BekensteinAlbert EinsteinFritz ZwickyVera RubinEmmy Noether
Tags
Standard Model entropy black hole
Laws
second law of thermodynamicsHawking radiationgravitational lensingNoether's theoremBekenstein-Hawking entropyEinstein field equations
Original: arXiv:2512.18400 · CC BY · bridge42worlds