Revision 2

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Changes against revision 1:

Title · changed: Revision 1: Does the pure square-lattice Hubbard model superconduct at moderate doping; Revision 2: Does the pure square-lattice Hubbard model superconduct at moderate doping?
Plain: With only nearest-neighbor hopping, the most accurate computer methods find stripes of charge and spin instead of superconductivity, but competing states lie very close in energy.
Precise: For the square-lattice Hubbard model with $t' = 0$, $U/t = 6\ \text{to}\ 8$ and hole doping $\delta = 1/8$, determine whether the ground state in the thermodynamic limit has long-range d-wave superconducting order or a stripe state whose pair correlations decay to zero. An answer is a controlled extrapolation of the pairing order parameter from at least two independent methods (DMRG, AFQMC, iPEPS, DMET) with consistent error bars.
Settled by: Agreement of independent unbiased methods on the extrapolated d-wave order parameter at $\delta=1/8$ with error bars smaller than its claimed value.
Kind: well-posed
Answer type: yes-no
References: (empty)
Literature status: partially-resolved
Status note: A multi-method study (2020) found filled stripes and no long-range d-wave order for $t' = 0$ at $\delta = 1/8$; competing uniform superconducting states lie close in energy.
Posed since: 1987

Decisions