Efimov State in the ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ Trimer

On the basis of a Faddeev calculation, an Efimov state is predicted to exist in ${}_{}{}^4{}_{}{}^{}\mathrm{He}_3^{}{}_{}{}^{}$. This discovery represents the first manifestation of the Efimov effect and may have farreaching consequences in the statistical mechanics of ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ gas at low temperatures.