Microscopic pair formation and pseudogap–superconductivity relationship in the 2D Fermi–Hubbard model

Investigate the microscopic mechanism of fermion pair formation and ascertain the relationship between the pseudogap phase and superconductivity in the two-dimensional Fermi–Hubbard model on the square lattice, focusing on regimes where only short-range pairing correlations are experimentally accessible.

Background

The paper proposes a protocol to measure pairing correlations in the two-dimensional Fermi–Hubbard model by implementing the attractive version of the model and using local gates to access singlet pairing correlations, including d-wave symmetry, in the repulsive model via a partial particle–hole transformation. Because current cold-atom platforms operate at temperatures where pairing correlations are short-ranged and decay exponentially, the authors argue that probing these short-range correlations is a necessary step toward understanding superconductivity in 2D Hubbard-type systems.

Within this context, the authors explicitly highlight outstanding open questions about the microscopic origin of pair formation and the connection between the pseudogap and superconductivity. Their measurement scheme is positioned as a tool to begin addressing these questions experimentally, even before long-range order is achieved in ultracold atom simulators.