Non-Fermi liquid scattering against an emergent Bose liquid: manifestations in the kink and other exotic quasiparticle behaviors in the normal-state cuprate superconductors

The normal state of cuprate superconductors exhibits many exotic behaviors qualitatively different from the Fermi liquid, the foundation of condensed matter physics. Here we demonstrate that non-Fermi liquid behaviors emerge naturally from scattering against an emergent Bose liquid. Particularly, we find a finite zero-energy scattering rate at low-temperature limit that grows linearly with respect to temperature, against clean fermions' generic non-dissipative characteristics. Surprisingly, three other seemingly unrelated experimental observations are also produced, including the well-studied "kink" in the quasi-particle dispersion, as well as the puzzling correspondences between the normal and superconducting state. Our findings provide a general route for fermionic systems to generate non-Fermi liquid behavior, and suggest strongly that by room temperature the doped holes in the cuprates have already formed an emergent Bose liquid of tightly bound pairs, whose low-temperature condensation gives unconventional superconductivity.