If a diffuse gas of atoms is trapped, cooled, and compressed, the de Broglie wavelengths of some atoms can become larger than the distance between atoms. The overlap between atoms leads to new states of matter. In one experiment, 87Rb atoms were cooled to 20 nK.

Required:
a. What is their de Broglie wavelength at this temperature?
b. How many times larger is this than the 0.47 nm diameter of the atoms?