ABSTRACT
In general, the expectation values of observable quantities depend on time. In quantum mechanics, these values are given by the expression: https://www.w3.org/1998/Math/MathML" display="block"> < X > t = < A ( t ) | X ( t ) | A ( t ) > . https://www.w3.org/1999/xlink" xlink:href="https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003436263/11a1814b-c2ab-4d89-be15-80efb520b7b3/content/math10_1.tif"/>
