Ground state phase diagram of the doped Hubbard model on the four-leg cylinder

The authors determine the ground state phase diagram of the lightly-doped Hubbard model on four leg cylinders with next-nearest-neighbor hopping, t'. The paper shows that, while the system remains insulating without t', it quickly evolves into two distinct superconducting Luther-Emery liquids for small t' with different spin and single particle properties.