Theory of amplification of sound (acoustic phonons) by absorption of   laser radiation in quantum wires with parabolic potential
  Based on the quantum transport equation for the electron-phonon system, the absorption coefficient of sound (acoustic phonons) by absorption of a laser radiation in quantum wires with parabolic potential is calculated for the case of monophoton absorption and the case of multiphoton absorption. Analytical expressions and conditions for the absorption coefficient of sound are obtained. Differences between the two cases of monophoton absorption and of multiphoton absorption are discussed; numerical computations and plots are carried out for a GaAs/GaAsAl quantum wire. The results are compared with bulk semiconductors and quantum wells. 
Nguyen Quoc Hung, Dinh Quoc Vuong, Nguyen Quang Bau