Small Group Activity: de Broglie wavelength after freefall

Contemporary Challenges 2021
In this activity students combine energy conservation with the relationship between the de Broglie wavelength and momentum to find the wavelength of atoms that have been dropped a given distance.

This activity follows Interference and quantum weirdness and requires at minimum the end of the lecture which discusses this experiment.

In Interference and quantum weirdness you learned about an experiment in which rubidium atoms are dropped from a trap into an optical two-slit experiment. During this experiment the atoms fall a total of 1.5 meters. What is the de Broglie wavelength of an atom after falling from rest 1.5 m? \begin{align} \lambda &= \frac{2\pi\hbar}{p} \end{align}

de Broglie wavelength gravity
Learning Outcomes