论文标题
计算机的包含热力学
Inclusive Thermodynamics of Computational Machines
论文作者
论文摘要
我们引入了一个框架,旨在分析抽象定义的逻辑计算机的热力学,例如确定性有限自动机(DFA)或图灵机,而无需指定实现计算机的物理过程的任何外部参数(例如速率矩阵,汉密尔顿人等)。早期对如何执行此操作的研究是基于随机热力学的连续时间马尔可夫链(CTMC)制定的。这些研究假设实施计算的物理系统产生的不可逆熵产生(EP)完全为零,或者允许EP为非零,但仅考虑EP的不匹配成本成分。此外,它们仅应用于单一类型的计算机。我们的框架既不要求EP等于零,也不要求关注EP的不匹配成本组成部分,并且旨在适用于所有类型的计算机。与使用基于CTMC的配方进行的早期研究相反,我们的框架基于包容性的哈密顿配方,其中感兴趣系统和浴室的结合在哈密顿量(或单一)动力学中进化。在这里,我们使用我们的框架来得出计算机的积分波动定理,其中预期值严格少于1。我们还得出了交换性波动定理,以及涉及第一次计算时间的不匹配成本公式。我们分析由DFA,Markov信息源和嘈杂的通信渠道生成的EP。特别是,我们使用Myhill-hearse Science定理来证明,在所有识别相同语言的DFA中,最小的复杂性DFA是所有动态和所有迭代的EP最小的DFA。
We introduce a framework designed to analyze the thermodynamics of an abstractly defined logical computer like a deterministic finite automaton (DFA) or a Turing machine, without specifying any extraneous parameters (like rate matrices, Hamiltonians, etc.) of a physical process that implements the computer. Earlier investigations of how to do this were based on the continuous-time Markov chain (CTMC) formulation of stochastic thermodynamics. These investigations either assumed that there was exactly zero irreversible entropy production (EP) generated by the physical system implementing the computation, or allowed the EP to be nonzero but only considered the mismatch cost component of the EP. In addition, they only applied to a single type of computer. Our framework neither requires that EP equal zero nor restricts attention to the mismatch cost component of EP, and is designed to apply to all types of computational machines. In contrast to earlier investigations using the CTMC-based formulation, our framework is based on the inclusive Hamiltonian formulation, in which the combination of the system of interest and the baths evolve in a Hamiltonian (or unitary) dynamics. Here, we use our framework to derive an integral fluctuation theorem for computers, in which the expectation value is strictly less than 1. We also derive an exchange fluctuation theorem, and a mismatch cost formula involving first-passage times. We analyze the EP generated by a DFA, a Markov information source, and a noisy communication channel. In particular, we use the Myhill-Nerode theorem of computer science to prove that out of all DFAs which recognize the same language, the minimal complexity DFA is the one with minimal EP for all dynamics and at all iterations.