  A spin density-wave quantum critical point (QCP) is the central organizing
principle of organic, iron-pnictide, heavy-fermion and electron-doped cuprate
superconductors. It accounts for the superconducting Tc dome, the
non-Fermi-liquid resistivity, and the Fermi-surface reconstruction. Outside the
magnetically ordered phase above the QCP, scattering and pairing decrease in
parallel as the system moves away from the QCP. Here we argue that a similar
scenario, based on a stripe-order QCP, is a central organizing principle of
hole-doped cuprate superconductors. Key properties of Eu-LSCO, Nd-LSCO and YBCO
are naturally unified, including stripe order itself, its QCP, Fermi-surface
reconstruction, the linear-T resistivity, and the nematic character of the
pseudogap phase.
