01981nas a2200241 4500008004100000245005400041210005400095260001300149520129500162100002501457700002301482700002001505700002001525700002201545700002201567700001401589700001901603700001801622700001801640700002001658700002401678856003701702 2021 eng d00aObservation of a prethermal discrete time crystal0 aObservation of a prethermal discrete time crystal c2/2/20213 a
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.
1 aKyprianidis, Antonis1 aMachado, Francisco1 aMorong, William1 aBecker, Patrick1 aCollins, Kate, S.1 aElse, Dominic, V.1 aFeng, Lei1 aHess, Paul, W.1 aNayak, Chetan1 aPagano, Guido1 aYao, Norman, Y.1 aMonroe, Christopher uhttps://arxiv.org/abs/2102.0169501563nas a2200169 4500008004100000245002700041210002700068260001400095300001200109490000700121520114400128100002201272700002401294700001801318700002001336856003701356 2020 eng d00aDiscrete Time Crystals0 aDiscrete Time Crystals c3/10/2020 a467-4990 v113 aExperimental advances have allowed for the exploration of nearly isolated quantum many-body systems whose coupling to an external bath is very weak. A particularly interesting class of such systems is those which do not thermalize under their own isolated quantum dynamics. In this review, we highlight the possibility for such systems to exhibit new non-equilibrium phases of matter. In particular, we focus on "discrete time crystals", which are many-body phases of matter characterized by a spontaneously broken discrete time translation symmetry. We give a definition of discrete time crystals from several points of view, emphasizing that they are a non-equilibrium phenomenon, which is stabilized by many-body interactions, with no analog in non-interacting systems. We explain the theory behind several proposed models of discrete time crystals, and compare a number of recent realizations, in different experimental contexts.
1 aElse, Dominic, V.1 aMonroe, Christopher1 aNayak, Chetan1 aYao, Norman, Y. uhttps://arxiv.org/abs/1905.13232