A cascade of non-Fermi liquid crossovers from an interplay of local and bosonic quantum criticality

We present examples of multi-orbital electronic lattice models, coupled to bosonic collective modes with modified Sachdev-Ye-Kitaev form of interactions, which become solvable when the number of orbitals and collective modes is taken to be large. At high energies, these models display non-Fermi liquid behavior with local quantum criticality and are described by a strongly coupled electron-boson fluid. As a function of decreasing energy scales, they exhibit a crossover into an incipient heavy Fermi liquid regime, where the interaction between the bosonic mode and the coherent electronic quasiparticles near the Fermi surface leads to Landau damping. When the boson gap is tuned to criticality, the feedback of the damped boson on the electrons leads to a low-temperature non-Fermi liquid with a critical Fermi surface. Our models thus describe a cascade of crossovers from a dynamical critical exponent z=∞ down to z=3 in a controlled setting as a function of decreasing energy scales.