Ultracold neutrons were produced by transferring momentum from fast neutrons to these particles in a 2011 paper by Piegsa et al. Hydrodynamic transport of these particles can result in very high thermal conductivity due to wavelike heat transfer. These particles (15[1])make up the linear portion of (15[1])a dispersion relation that also includes maxons and rotons in superfluid helium. (-5[1])Scattering between two of these particles can occur by a normal or an (*) Umklapp process. Depending on whether neighboring atoms are in or out (10[1]-5[1])of phase, these quasiparticles are classified (10[3])as (10[2])“optical” or “acoustic.” (10[7])In a crystal, these quasiparticles can (10[1])be derived by considering each (10[1])atom in its (10[2])lattice site (10[1])as a harmonic (-5[1])oscillator and then (10[2])taking (-5[1])the normal (10[3]-5[1])modes. For 10 points, name (-5[1])these quasiparticles that are the quanta of (10[1])sound. (10[1])■END■ (10[1]0[5])