Pizzi Andrea, Nunnenkamp Andreas, Knolle Johannes
Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom.
School of Physics and Astronomy and Centre for the Mathematics and Theoretical Physics of Quantum Non-Equilibrium Systems, University of Nottingham, Nottingham NG7 2RD, United Kingdom.
Phys Rev Lett. 2021 Oct 1;127(14):140602. doi: 10.1103/PhysRevLett.127.140602.
Systems subject to a high-frequency drive can spend an exponentially long time in a prethermal regime, in which novel phases of matter with no equilibrium counterpart can be realized. Because of the notorious computational challenges of quantum many-body systems, numerical investigations in this direction have remained limited to one spatial dimension, in which long-range interactions have been proven a necessity. Here, we show that prethermal nonequilibrium phases of matter are not restricted to the quantum domain. Studying the Hamiltonian dynamics of a large three-dimensional lattice of classical spins, we provide the first numerical proof of prethermal phases of matter in a system with short-range interactions. Concretely, we find higher-order as well as fractional discrete time crystals breaking the time-translational symmetry of the drive with unexpectedly large integer as well as fractional periods. Our work paves the way toward the exploration of novel prethermal phenomena by means of classical Hamiltonian dynamics with virtually no limitations on the system's geometry or size, and thus with direct implications for experiments.
受到高频驱动的系统可能会在预热状态下花费指数级长的时间，在这种状态下可以实现没有平衡对应物的新型物质相。由于量子多体系统存在众所周知的计算挑战，在这个方向上的数值研究一直局限于一维空间，在一维空间中长程相互作用已被证明是必要的。在这里，我们表明物质的预热非平衡相并不局限于量子领域。通过研究经典自旋的大型三维晶格的哈密顿动力学，我们提供了具有短程相互作用的系统中物质预热相的首个数值证明。具体而言，我们发现高阶以及分数阶离散时间晶体打破了驱动的时间平移对称性，其具有意想不到的大整数以及分数周期。我们的工作为通过经典哈密顿动力学探索新型预热现象铺平了道路，这种方法对系统的几何形状或尺寸几乎没有限制，因此对实验有直接影响。
