Solutions to Schrödinger’s equation for a lattice may be crudely approximated with one of these potentials obtained by shrinking the width of the wells in the Kronig–Penney model. For 10 points each:
[10h] Name this potential sometimes denoted with a Cyrillic “sha.” Like Gaussians, this potential has a self-transforming property with respect to Fourier transforms.
ANSWER: Dirac comb [accept impulse train or sampling function; prompt on comb]
[10e] The Dirac comb is built from an infinite sum of translations of a distribution denoted by this letter that is often misleadingly called a “function.” In physics, this letter typically denotes the change in a given quantity.
ANSWER: delta [accept capital delta or lowercase delta; accept Dirac delta distribution/function]
[10m] For a single Dirac delta potential, positive-energy solutions are named for these processes. The Born approximation simplifies computations of a quantity in these processes measured in units of “barns.”
ANSWER: scattering processes [accept word forms; anti-prompt on nuclear reactions]
<JC, Physics>