... beginning of the first line to the end of the second; then the line joining the beginning of the second to the end of the first is the line that represents the sum of the two wavefunctions This is ... that the width of the peak is also related to the uncertainty in the velocity of the particle, more precisely the velocity in the direction of the line between the points and P , only here the ... race; in these cases they enter because of our lack of precise knowledge of the orginal state of the system, whereas in quantum theory, even if we had complete knowledge of the initial state, the...