Uncertainty principle (wikipedia) Where ħ is the reduced Planck constant.
The original heuristic argument that such a limit should exist was given by Heisenberg, after whom it is sometimes named the Heisenberg principle. This ascribes the uncertainty in the measurable quantities to the jolt-like disturbance triggered by the act of observation. Though widely repeated in textbooks, this physical argument is now known to be fundamentally misleading.[4][5] While the act of measurement does lead to uncertainty, the loss of precision is less than that predicted by Heisenberg's argument; the formal mathematical result remains valid, however. Since the uncertainty principle is such a basic result in quantum mechanics, typical experiments in quantum mechanics routinely observe aspects of it. The Heisenberg uncertainty principle. HeisenbergUncertainty Principle (Basic Concepts of the QuantumTheory (I)) Commutator (Ring Theory - Math)