



@article {2768,
	title = {Observation of a prethermal discrete time crystal},
	year = {2021},
	month = {2/2/2021},
	abstract = {<p>The conventional framework for defining and understanding phases of matter requires thermodynamic equilibrium. Extensions to non-equilibrium systems have led to surprising insights into the nature of many-body thermalization and the discovery of novel phases of matter, often catalyzed by driving the system periodically. The inherent heating from such Floquet drives can be tempered by including strong disorder in the system, but this can also mask the generality of non-equilibrium phases. In this work, we utilize a trapped-ion quantum simulator to observe signatures of a non-equilibrium driven phase without disorder: the prethermal discrete time crystal (PDTC). Here, many-body heating is suppressed not by disorder-induced many-body localization, but instead via high-frequency driving, leading to an expansive time window where non-equilibrium phases can emerge. We observe a number of key features that distinguish the PDTC from its many-body-localized disordered counterpart, such as the drive-frequency control of its lifetime and the dependence of time-crystalline order on the energy density of the initial state. Floquet prethermalization is thus presented as a general strategy for creating, stabilizing and studying intrinsically out-of-equilibrium phases of matter.</p>},
	url = {https://arxiv.org/abs/2102.01695},
	author = {Antonis Kyprianidis and Francisco Machado and William Morong and Patrick Becker and Kate S. Collins and Dominic V. Else and Lei Feng and Paul W. Hess and Chetan Nayak and Guido Pagano and Norman Y. Yao and Christopher Monroe}
}
@article {1271,
	title = {Many-body localization in a quantum simulator with programmable random  disorder},
	journal = {Nature Physics},
	year = {2016},
	month = {2016/06/06},
	abstract = {<p>When a system thermalizes it loses all local memory of its initial conditions. This is a general feature of open systems and is well described by equilibrium statistical mechanics. Even within a closed (or reversible) quantum system, where unitary time evolution retains all information about its initial state, subsystems can still thermalize using the rest of the system as an effective heat bath. Exceptions to quantum thermalization have been predicted and observed, but typically require inherent symmetries or noninteracting particles in the presence of static disorder. The prediction of many-body localization (MBL), in which disordered quantum systems can fail to thermalize in spite of strong interactions and high excitation energy, was therefore surprising and has attracted considerable theoretical attention. Here we experimentally generate MBL states by applying an Ising Hamiltonian with long-range interactions and programmably random disorder to ten spins initialized far from equilibrium. We observe the essential signatures of MBL: memory retention of the initial state, a Poissonian distribution of energy level spacings, and entanglement growth in the system at long times. Our platform can be scaled to higher numbers of spins, where detailed modeling of MBL becomes impossible due to the complexity of representing such entangled quantum states. Moreover, the high degree of control in our experiment may guide the use of MBL states as potential quantum memories in naturally disordered quantum systems.</p>},
	doi = {10.1038/nphys3783},
	url = {http://arxiv.org/abs/1508.07026v1},
	author = {Jacob Smith and Aaron Lee and Philip Richerme and Brian Neyenhuis and Paul W. Hess and Philipp Hauke and Markus Heyl and David A. Huse and Christopher Monroe}
}
