Suppression of Heating by Multi-color Driving Protocols in Floquet Engineered Strongly Correlated Systems

TL;DR

This paper demonstrates that multi-color driving protocols can effectively suppress heating in Floquet-engineered strongly correlated systems, enabling better control of their physical properties and revealing significant Floquet-induced effects.

Contribution

It introduces a method using auxiliary excitations to interfere with absorption processes, reducing heating in driven Hubbard models, and explores its impact on spin exchange interactions.

Findings

Heating suppression achieved with multi-color driving protocols.

Effective control of low-energy physics through Floquet engineering.

Suppression of 2-photon and 3-photon absorption processes.

Abstract

Heating effects in Floquet engineered system are detrimental to the control of physical properties. In this work, we show that the heating of periodically driven strongly correlated systems can be suppressed by multi-color driving, i.e., by applying auxiliary excitations which interfere with the absorption processes from the main drive. We focus on the Mott insulating single-band Hubbard model and study the effects of multi-color driving with nonequilibrium dynamical mean-field theory. The main excitation is a periodic electric field with frequency $\Omega$ smaller than the Mott gap, while for the auxiliary excitations, we consider additional electric fields and/or hopping modulations with a higher harmonic of $\Omega$. To suppress the 3-photon absorption of the main excitation, which is a parity-odd process, we consider auxiliary electric-field excitations and a combination of electric-field excitations and hopping modulations. On the other hand, to suppress the 2-photon absorption, which is a parity-even process, we consider hopping modulations. The conditions for an efficient suppression of heating are well captured by the Floquet effective Hamiltonian derived with the high-frequency expansion in a rotating frame. As an application, we focus on the exchange couplings of the spins (pseudo-spins) in the repulsive (attractive) model, and demonstrate that the suppression of heating allows to realize and clearly observe a significant Floquet-induced change of the low energy physics.