Elastic and transport coefficients of the perfect hard-sphere crystal from the poles of the hydrodynamic spectral functions

Abstract: The elastic and transport coefficients of a perfect face-centered cubic crystal of hard spheres are computed from the poles of the dynamic structure factor and of the spectral functions of transverse momentum density fluctuations. For such crystals, the relevant coefficients are the three isothermal elastic constants $(C_{11}<sup>T,C_{12}<sup>T,C_{44}<sup>T)$, the heat conductivity $\kappa$, and the three viscosities $(\eta_{11},\eta_{12},\eta_{44})$ (in Voigt's notations), which are directly computed using molecular dynamics simulations. The elastic and transport coefficients are then compared to the values of the same coefficients obtained with the method of Helfand moments, showing good agreement and providing strong support for the microscopic hydrodynamic theory of perfect crystals based on the local-equilibrium approach.