Proof Mooted For Heisenberg's Uncertainty Principle

ananyo writes "Encapsulating the strangeness of quantum mechanics is a single mathematical expression. According to every undergraduate physics textbook, the uncertainty principle states that it is impossible to simultaneously know the exact position and momentum of a subatomic particle — the more precisely one knows the particle's position at a given moment, the less precisely one can know the value of its momentum. But the original version of the principle, put forward by physicist Werner Heisenberg in 1927, couches quantum indeterminism in a different way — as a fundamental limit to how well a detector can measure quantum properties. Heisenberg offered no direct proof for this version of his principle. Now researchers say they have such a proof. (Pre-print available at the arXiv.) If they're right, it would put the measurement aspect of the uncertainty principle on solid ground — something that researchers had started to question — but it would also suggest that quantum-encrypted messages can be transmitted securely."

Comments

Uncertaintiy principle and Foruier Transforms

[Grantbridge]

The uncertainty principle is the same as taking a Fourier transform of a sound pulse. If the time of the wave is short then the uncertainty in the frequency is high, and you get a large width in frequency space. If the wave is on for a long time, you get a nice sine wave and the uncertainty in the frequency is low, but the uncertainty in the time is now high. The maths for momentum/position of electrons comes out the same as time/frequency of sound waves. You get the uncertainty principle with non-quantised waves anyway, its not magic!