Stress-free spatial anisotropy in phase ordering.

We predict late-time spatial anisotropy for scalar systems with anisotropic surface tension undergoing dissipative quenches below their critical temperature. Spatial anisotropy is confirmed numerically for two-dimensional Ising models with critical and off-critical quenches and with both conserved and nonconserved dynamics. Due to the nonzero anisotropy, expected in all lattice systems, correlation functions in the scaling limit depend on temperature, microscopic interactions, dynamics, disorder, and frustration.