The concept of “Floquet engineering” relies on an external periodic drive to realize novel, effectively static Hamiltonians. This technique is being explored in experimental platforms across physics, including ultracold atoms, laser-driven electron systems, nuclear magnetic resonance, and trapped ions. The key challenge in Floquet engineering is to avoid the uncontrolled absorption of photons from the drive, especially in interacting systems in which the excitation spectrum becomes effectively dense. The resulting dissipative coupling to higher-lying modes, such as the excited bands of an optical lattice, has been explored in recent experimental and theoretical works, but the demonstration of a broadly applicable method to mitigate this effect is lacking. Here, we show how two-path quantum interference applied to strongly correlated fermions in a driven optical lattice suppresses dissipative coupling to higher bands and increases the lifetime of double occupancies and spin correlations by 2 to 3 orders of magnitude. Interference is achieved by introducing a weak second modulation at twice the fundamental driving frequency with a definite relative phase. This technique is shown to suppress dissipation in both weakly and strongly interacting regimes of an off-resonantly driven Hubbard system, opening an avenue to realizing low-temperature phases of matter in interacting Floquet systems.

中文翻译：

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抑制Floquet-Hubbard系统中的耗散

“ Floquet工程”的概念依赖于外部周期性驱动来实现新颖，有效的静态哈密顿量。这项技术正在整个物理学的实验平台上进行探索，包括超冷原子，激光驱动的电子系统，核磁共振和捕获离子。Floquet工程中的关键挑战是避免从驱动器中无节制地吸收光子，特别是在相互作用系统中，其中激发光谱会变得有效密集。在最近的实验和理论工作中已经探索了与较高模式（例如光学晶格的激发带）的耗散耦合，但是缺乏减轻这种影响的广泛适用方法的论证。这里，我们展示了如何在驱动的光学晶格中将二路径量子干扰应用于强相关费米子，从而抑制与较高频带的耗散耦合，并使双重占据和自旋相关的寿命增加2到3个数量级。通过以两倍的基本驱动频率和确定的相对相位引入微弱的第二调制来实现干扰。该技术可以抑制在非共振驱动的Hubbard系统的弱相互作用和强相互作用状态下的耗散，从而为在相互作用的Floquet系统中实现物质的低温相开辟了一条途径。通过以两倍的基本驱动频率和确定的相对相位引入微弱的第二调制来实现干扰。该技术可以抑制在非共振驱动的Hubbard系统的弱相互作用和强相互作用状态下的耗散，从而为在相互作用的Floquet系统中实现物质的低温相开辟了一条途径。通过以两倍的基本驱动频率和确定的相对相位引入微弱的第二调制来实现干扰。该技术可以抑制在非共振驱动的Hubbard系统的弱相互作用和强相互作用状态下的耗散，从而为在相互作用的Floquet系统中实现物质的低温相开辟了一条途径。