They are the standard deviations of the position and momentum operators, respectively. They are defined as follows:
\[\Delta x = \sqrt{\langle x^{2} \rangle - \langle x \rangle^{2}}\]
\[\Delta p_{x} = \sqrt{\langle p_{x}^{2} \rangle - \langle p_{x} \rangle^{2}}\]
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