Rudolf Peierls ("PIE-earls") demonstrated that momentum isn't conserved in a scattering process that involves three of these particles and is balanced by a nonzero k-space vector.
A frequency for these particles contains a factor of the cube root of "six pi squared times number density." Their spectrum has dips due to the presence of a Fermi surface in the Kohn anomaly. Rudolf Peierls ("PIE-earls") demonstrated that momentum isn't conserved in a scattering process that involves three of these particles and is balanced by a nonzero k-space vector. Their interactions with electrons lead to the formation of Cooper pairs in BCS theory. On a plot of frequency versus wavevector, the dispersion curves that touch the origin correspond to "acoustic" particles of this type. Imposing a cutoff frequency for these particles leads to a temperature-cubed dependence for heat capacity at low temperatures in the Debye (deh-"BYE") model. For 10 points, what quasi-particles are the quanta of energy for lattice vibrations?
A frequency for these particles contains a factor of the cube root of "six pi squared times number density.
phonons