2 problems

Consider an infinite solid phase, and let $\Gamma^{\mathrm{c.m.}}_{\infty}$ be the probability of infinite total momentum. For a crystal, let ${\mathbb L}^*$ be the reciprocal latt…

Let ${\bf P}$ denote the total momentum of an infinite quantum system, and distinguish an infinite solid from a crystal, whose momentum distribution is supported on a reciprocal la…