Stripe order enhanced superconductivity in the Hubbard model

Unidirectional (``stripe'') charge-density-wave order has now been established as a ubiquitous feature in the phase diagram of the cuprate high temperature (HT) superconductors, where it generally competes with superconductivity (SC).  None-the-less, on theoretical grounds it has  been conjectured that stripe order (or other forms of ``optimal'' inhomogeneities) may play an essential positive role in the mechanism of HTSC.  Here we report density matrix renormalization group studies of the Hubbard model on long 4 and 6 leg cylinders where the hopping matrix elements transverse to the long direction are periodically modulated - mimicing the effect of putative period-2 stripe order.  We find even modest amplitude modulations can enhance the long-distance SC correlations by many orders of magnitude, and drive the system into a phase with a substantial spin gap and SC quasi-long-range-order with a Luttinger exponent, K_sc ~ 1.