When does a physical system compute?

作者：Horsman Clare^*; Stepney Susan; Wagner Rob C; Kendon Viv

来源：Proceedings of the Royal Society A-Mathematical Physical and Engineering Sciences, 2014, 470(2169): 20140182.

DOI：10.1098/rspa.2014.0182

• computation
• physical computation
• computer

Computing is a high-level process of a physical system. Recent interest in non-standard computing systems, including quantum and biological computers, has brought this physical basis of computing to the forefront. There has been, however, no consensus on how to tell if a given physical system is acting as a computer or not; leading to confusion over novel computational devices, and even claims that every physical event is a computation. In this paper, we introduce a formal framework that can be used to determine whether a physical system is performing a computation. We demonstrate how the abstract computational level interacts with the physical device level, in comparison with the use of mathematical models in experimental science. This powerful formulation allows a precise description of experiments, technology, computation and simulation, giving our central conclusion: physical computing is the use of a physical system to predict the outcome of an abstract evolution. We give conditions for computing, illustrated using a range of nonstandard computing scenarios. The framework also covers broader computing contexts, where there is no obvious human computer user. We introduce the notion of a %26apos;computational entity%26apos;, and its critical role in defining when computing is taking place in physical systems.

• 出版日期2014-9-8