Backreaction of Dirac Matter in the Context of the SYK Model: Non-Gaussian Random Couplings and Bulk Mass Deformations

Abstract: We elaborate further on the backreaction of Dirac matter in the SYK framework, incorporating non-Gaussian coupling distributions and bulk fermion mass effects. Our study analyzes quartic matter couplings generated by a non-Gaussian distribution as an illustrative example. The introduction of bulk-fermion mass alters the boundary coupling between the Dirac and Majorana fermions. The averaged adjacent gap ratio is sensitive to the distribution of random couplings, which remains independent of the Hamiltonian's symmetry. The generalization of the SYK model to non-Gaussian distributions and the inclusion of bulk fermion mass remain qualitatively similar to the Gaussian and massless cases. Key deviations manifest only in the time scales for the linear ramp in the spectral form factor and entanglement entropy saturation.