Question

Multiple choice:

When do quantum effects become important?

a) at low density and high temperature

b) at low density and low temperature

c) at high density and high temperature

d) at high density and low temperature

Please explain. It's for a statistical mechanics class

Answer 1

Quantum effects are important when the distance between the particles is smaller than the quantum wavelength associated with the particle. When this happens, the wave packets of adjacent particle overlap and thus we switch from classical regime to quantum regime.

This happens when temperatures are very low and density is very high. At low temperature, particles does not have enough kinetic energy and thus are close together making it a high density state.

option d) is correct.