Universal transport in periodically driven systems without long-lived quasiparticles

Abstract

An intriguing regime of universal charge transport at high entropy density has been proposed for periodically driven interacting one-dimensional systems with Bloch bands separated by a large single-particle band gap. For weak interactions, a simple picture based on well-defined Floquet quasiparticles suggests that the system should host a quasisteady state current that depends only on the populations of the system's Floquet-Bloch bands and their associated quasienergy winding numbers.Here we show that such topological transport persists into the strongly interacting regime where the single-particle lifetime becomes shorter than the drive period. Analytically, we show that the value of the current is insensitive to interaction-induced band renormalizations and lifetime broadening when certain conditions are met by the system's non-equilibrium distribution function. We show that these conditions correspond to a quasisteady state. We support these predictions through numerical simulation of a system of strongly interacting fermions in a periodically-modulated chain of Sachdev-Ye-Kitaev dots. Our work establishes universal transport at high entropy density as a robust far from equilibrium topological phenomenon, which can be readily realized with cold atoms in optical lattices.

Breakdown of quantisation in a Hubbard-Thouless pump

“…The presence of interactions can profoundly affect topological charge pumps and their symmetries, which has sparked significant and ongoing theoretical interest [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43]. In the strongly repulsive limit of the Rice-Mele model (U t, |∆|, |δ|) the region of bond-centred inversion symmetry extends across the plane in Fig.…”

Analytic studies on the SYK models: from instantaneous thermalization to holographic duality

“…With SYK-type chains, many large-N problems become tractable despite a lack in integrability [33,59,127,[153][154][155][156]]. Here we focus on such chains of coupled dots…”

“…A current may still be induced in various ways. For instance, if one couple the dots via a time-periodic Rice-Mele Hamiltonian, one can implement a Thouless charge pump [155]. A slowly varying magnetic vector potential, included via Peierls substitution [33], with quadratic SYK hopping, also yields a current with a quadratic to linear in T resistivity crossover discussed in Sec.…”