All computation is physically embedded. Reflecting this, a growing body of results embraces rate equations as the underlying mechanics of thermodynamic computation and biological information processing. Strictly applying the implied continuous-time Markov chains, however, excludes a universe of natural computing. We show that expanding the toolset to continuous-time hidden Markov chains substantially removes the constraints. The general point is made concrete by our analyzing two eminently-useful computations that are impossible to describe with a set of rate equations over the memory states. We design and analyze a thermodynamically-costless bit flip, providing a first counterexample to rate-equation modeling. We generalize this to a costless Fredkin gate---a key operation in reversible computing that is computation universal. Going beyond rate-equation dynamics is not only possible, but necessary if stochastic thermodynamics is to become part of the paradigm for physical information processing.
Markov length can diverge in systems whose universal physics is spatially Markovian
University of California at San Diego（加利福尼亚大学圣地亚哥分校）；Kavli Institute for Theoretical Physics, University of California, Santa Barbara（加州大学圣塔芭芭拉分校卡弗里理论物理研究所）
Universal Precision Limits in General Open Quantum Systems
Center for Gravitational Physics and Quantum Information, Yukawa Institute for Theoretical Physics, Kyoto University（京都大学汤川理论物理研究所引力物理与量子信息中心）；Department of Physics, Kyoto University（京都大学物理学系）
Universal Thermodynamic Uncertainty Relation in Non-Equilibrium Dynamics
我们推导出一个普遍的热力学不确定性关系（TUR），适用于在一般的马尔可夫系统中的任意观察。我们的结果的一般性使我们能够得到两个发现：（1）对于任意的非平衡系统，熵产生和\textit{degree of non-stationarity}都需要严格约束热力学流的强度;（2）通过去除对可观测量的反对称约束，物理学中的TUR和理论金融学中的一个基本不等式可以统一在一个框架中.
