TY - JOUR T1 - Absence of Thermalization in Finite Isolated Interacting Floquet Systems JF - Physical Review B Y1 - 2018 A1 - Karthik Seetharam A1 - Paraj Titum A1 - Michael Kolodrubetz A1 - Gil Refael AB -
Conventional wisdom suggests that the long time behavior of isolated interacting periodically driven (Floquet) systems is a featureless maximal entropy state characterized by an infinite temperature. Efforts to thwart this uninteresting fixed point include adding sufficient disorder to realize a Floquet many-body localized phase or working in a narrow region of drive frequencies to achieve glassy non-thermal behavior at long time. Here we show that in clean systems the Floquet eigenstates can exhibit non-thermal behavior due to finite system size. We consider a one-dimensional system of spinless fermions with nearest-neighbor interactions where the interaction term is driven. Interestingly, even with no static component of the interaction, the quasienergy spectrum contains gaps and a significant fraction of the Floquet eigenstates, at all quasienergies, have non-thermal average doublon densities. We show that this non-thermal behavior arises due to emergent integrability at large interaction strength and discuss how the integrability breaks down with power-law behavior in system size.
VL - 97 U4 - 014311 UR - https://journals.aps.org/prb/abstract/10.1103/PhysRevB.97.014311 CP - 1 U5 - 10.1103/PhysRevB.97.014311 ER -