Scattering with emergent charge-2e bosons produces pseudo-gap behavior and non-Fermi liquid scattering rate in electrons

By studying one-body and two-body spectral functions in the low-density regime of the 2D attractive Hubbard model via determinant quantum Monte Carlo, we demonstrate the emergence of long-lived charge-2e local bosonic bound state of bi-fermion. In the intermediate interacting strength, coexistence of such emergent bosons with unbound electrons is realized. Due to coupling with the uncondensed emergent bosons above the superconducting temperature, the unbound fermions display pseudo-gap behavior and non-Fermi liquid scattering rate as observed in the cuprates. Our results provide a strong support to previous emergent boson-based proposals for unconventional superconductivity and strange metal transport observed in many strongly correlated materials.