uncertainty principle

Canonical commutation rule for position q and momentum p variables of a particle, 1927. pq − qp = h/(2πi). Uncertainty principle of Heisenberg, 1927. German physicist Werner Heisenberg (1901–1976), who introduced Uncertainty Principle in 1927 The uncertainty principle, also known as Heisenberg's indeterminacy principle, is a fundamental concept in quantum mechanics. It states that there is a limit to the precision with which certain pairs of physical properties, such as position and momentum, can be simultaneously known. In other words, the more accurately one property is measured, the less accurately the other property can be known.

More formally, the uncertainty principle is any of a variety of mathematical inequalities asserting a fundamental limit to the product of the accuracy of certain related pairs of measurements on a quantum system, such as position, x, and momentum, p. Such paired-variables are known as complementary variables or canonically conjugate variables.