Universal quench dynamics of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>q</mml:mi></mml:math>-fermion Yukawa-Sachdev-Ye-Kitaev models

We study the quantum quench of the Yukawa-Sachdev-Ye-Kitaev model and one of its random hopping extensions with <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mi>q</a:mi></a:math> fermions and one boson. Several equilibrium properties are computed for general <b:math xmlns:b="http://www.w3.org/1998/Math/MathML"><b:mi>q</b:mi></b:math> with different parameter scaling within the large-<c:math xmlns:c="http://www.w3.org/1998/Math/MathML"><c:mi>N</c:mi></c:math> dynamical mean-field scheme. The non-Fermi liquid quench dynamics are studied by integrating the Kadanoff-Baym equations for switching off the random hopping term with constant Yukawa coupling or quenching to different final Yukawa couplings. The postquench oscillations and relaxation dynamics are insensitive to the quench amplitudes deep inside the non-Fermi liquid phase. With weak hopping coupling quenches, we find universal thermalization dynamics similar to the SYK model; however, with two temperatures and two distinct relaxation rates for bosons and fermions, both signal Planckian relaxations without quasiparticles, as in strange metals.