# What is uncertainty principle?

• (noun): (quantum theory) the theory that it is impossible to measure both energy and time (or position and momentum) completely accurately at the same time.
Synonyms: indeterminacy principle

## Uncertainty Principle

In quantum mechanics, the uncertainty principle is any of a variety of mathematical inequalities asserting a fundamental limit to the precision with which certain pairs of physical properties of a particle, such as position x and momentum p, can be known simultaneously. The more precisely the position of some particle is determined, the less precisely its momentum can be known, and vice versa. The original heuristic argument that such a limit should exist was given by Werner Heisenberg in 1927, after whom it is sometimes named, as the Heisenberg principle. A more formal inequality relating the standard deviation of position σx and the standard deviation of momentum σp was derived by Earle Hesse Kennard later that year (and independently by Hermann Weyl in 1928),

### Some articles on uncertainty principle:

Uncertainty Principle - Critical Reactions - Free Will
... Heisenberg have suggested that the uncertainty principle, or at least the general probabilistic nature of quantum mechanics, could be evidence for the two-stage model of free will ...
Short-time Fourier Transform - Resolution Issues
... This property is related to the Heisenberg uncertainty principle, but it is not a direct relationship – see Gabor limit for discussion ... The boundary of the uncertainty principle (best simultaneous resolution of both) is reached with a Gaussian window function, as the Gaussian minimizes the Fourier ...
Planck Constant - Origins - Uncertainty Principle
... constant also occurs in statements of Werner Heisenberg's uncertainty principle ... Given a large number of particles prepared in the same state, the uncertainty in their position, Δx, and the uncertainty in their momentum (in the ... The either-or nature of uncertainty forces measurement attempts to choose between trade offs, and given that they are quanta, the trade offs often take the form of either-or (as in Fourier analysis ...
Determinism - Modern Perspectives - Quantum Mechanics and Classical Physics - Quantum Realm
... The Heisenberg uncertainty principle is frequently confused with the observer effect ... The uncertainty principle actually describes how precisely we may measure the position and momentum of a particle at the same time — if we increase the accuracy in measuring ... These uncertainty relations give us that measure of freedom from the limitations of classical concepts which is necessary for a consistent description of atomic processes." On the topic of ...

### Famous quotes containing the word principle:

From the age of fifteen, dogma has been the fundamental principle of my religion: I know no other religion; I cannot enter into the idea of any other sort of religion; religion, as a mere sentiment, is to me a dream and a mockery.
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