Density of (s.p.) states: 3D ultra-relativistic particles Finally, let's go back to Eq. (8). Follow the steps discussed in Ch.IX for obtaining the density of single-particle (s.p.) states, show that g(ϵ) is given by g(ϵ)=4πV/c₃h₃ϵ²
for 3D ultra-relativistic (non-interacting) particles. [Hint: It is about fitting waves to a volume V and using the dispersion relation ϵ=cp=cℏk.]