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The Heisenberg uncertainty principle

Statement

Δx Δp≥ℏ/2\Delta x \, \Delta p \geq \hbar/2 — the product of the uncertainties in a particle’s position and momentum can never be smaller than the fixed bound ℏ/2\hbar/2.

Why is it true?

This is not a limitation of measuring instruments — it is an intrinsic property of nature: a particle cannot simultaneously have perfectly definite position and momentum, a mathematical consequence of matter's wave nature.

A Gaussian wave packet: squeeze it in x and the momentum spectrum spreads, and vice versa. The Δx, Δp readouts always satisfy Δx·Δp ≥ ħ/2.

Stated by

Topics that use this theorem

Related theorems

Step-by-step proofs

No step-by-step proof yet for this theorem.

References

  1. Werner Heisenberg (1927). Über den anschaulichen Inhalt der quantentheoretischen Kinematik und Mechanik