Controlling interactions is the key element for the quantum engineering of many-body systems. Using time-periodic driving, a naturally given many-body Hamiltonian of a closed quantum system can be transformed into an effective target Hamiltonian that exhibits vastly different dynamics. We demonstrate such Floquet engineering with a system of spins represented by Rydberg states in an ultracold atomic gas. By applying a sequence of spin manipulations, we change the symmetry properties of the effective Heisenberg XYZ Hamiltonian. As a consequence, the relaxation behavior of the total spin is drastically modified. The observed dynamics can be qualitatively captured by a semiclassical simulation. Engineering a wide range of Hamiltonians opens vast opportunities for implementing quantum simulation of nonequilibrium dynamics in a single experimental setting.

中文翻译：

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孤立多体自旋系统的 Floquet Hamiltonian 工程

控制相互作用是多体系统量子工程的关键要素。使用时间周期驱动，一个自然给定的封闭量子系统的多体哈密顿量可以转化为一个有效的目标哈密顿量，它表现出截然不同的动力学。我们用超冷原子气体中的里德堡态表示的自旋系统展示了这种 Floquet 工程。通过应用一系列自旋操作，我们改变了有效海森堡 XYZ 哈密顿量的对称性。结果，总自旋的弛豫行为被彻底改变。观察到的动态可以通过半经典模拟来定性地捕捉。