Many-body theory of magneto-elasticity in one dimension
  We construct a many-body theory of magneto-elasticity in one dimension and show that the dynamical correlation functions of the quantum magnet, connecting the spins with phonons, involve all energy scales. Accounting for all magnetic states non-perturbatively via the exact diagonalisation techniques of Bethe ansatz, we find that the renormalisation of the phonon velocity is a non-monotonous function of the external magnetic field and identify a new mechanism for attenuation of phonons - via hybridisation with the continuum of excitations at high energy. We conduct ultrasonic measurements on a high-quality single crystal of the frustrated spin-1/2 Heisenberg antiferromagnet $\textrm{Cs}_{2}\textrm{CuCl}_{4}$ in its one-dimensional regime and confirm the theoretical predictions, demonstrating that ultrasound can be used as a powerful probe of strong correlations in one dimension. 
O. Tsyplyatyev, P. Kopietz, Y. Tsui, B. Wolf, P. T. Cong, N. van Well,   F. Ritter, C. Krellner, W. A{\ss}mus, M. Lang
cond-mat.mes-hall