I've been exposed to two different interpretations of the uncertainty principle.(adsbygoogle = window.adsbygoogle || []).push({});

1) If an electron is in a certain state, a measurement of its position will yield a definite result. However, if after the measurement the electron could be returned to the same state, then a repeated measurement of its position will yield a different answer. Same holds for measurements of momentum. However, the standard deviation of the distribution for positions * the standard deviation for the distribution for momentum will always be greater than a certain constant.

2) Measurements are fuzzy. Measurements of, say, position will never yield a definite result, unless the momentum becomes completely unknown.

Which one is right?

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# Uncertainty principle and electrons

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