Exponents for sound attenuation near critical points in solids

Abstract

The expansion in $4-d=\epsilon$ is used to calculate exponents governing sound attenuation above a critical point. For SrTi${\mathrm{O}}_3$, exponents differing from previous predictions are predicted to govern the sound attenuation for all directions and polarizations. The predictions are also compared with recent measurements on BaMn${\mathrm{F}}_4$.