Heisenberg’s Uncertainty Principle

Heisenberg’s Uncertainty Principle is one of the fundamental concepts of Quantum Physics, and is the basis for the initial realization of fundamental uncertainties in the ability of an experimenter to measure more than one quantum variable at a time. Attempting to measure an elementary particle’s position to the highest degree of accuracy, for example, leads to an increasing uncertainty in being able to measure the particle’s momentum to an equally high degree of accuracy. Heisenberg’s Principle is typically written mathematically in either of two forms:

DE Dt ³ h / 4 p Dx Dp ³ h / 4 p

In essence, the uncertainty in the energy (DE) times the uncertainty in the time (Dt) -- or alternatively, the uncertainty in the position (Dx) multiplied times the uncertainty in the momentum (Dp) -- is greater or equal to a constant (h/4p). The constant, h, is called Planck’s Constant (where h/4p = 0.527 x 10^-34 Joule-second).