Pictorial energy () landscape for a finite-size set of soft spheres for which thermal fluctuations can be neglected. denotes the degree of freedom of particle positions, and the deformation of the shape of the simulation box. Dagois-Bohy et al. show that jammed states identified by compression-only (CO) methods minimize the energy with respect to the particles’ positions only and may be unstable to shear. Shear-stabilized packings (SS) minimize the energy with respect to both particle positions and the box shape and are thus properly jammed. Goodrich et al. analyze how the properties of shear- and compression-stable states scale with size, finding the evidence that jamming can be described as a true phase transition.