Computing exponentially faster: implementing a non- deterministic universal Turing machine using DNA



Currin, Andrew, Korovin, Konstantin, Ababi, Maria, Roper, Katherine, Kell, Douglas B ORCID: 0000-0001-5838-7963, Day, Philip J and King, Ross D
(2017) Computing exponentially faster: implementing a non- deterministic universal Turing machine using DNA. JOURNAL OF THE ROYAL SOCIETY INTERFACE, 14 (128). 20160990-.

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Abstract

The theory of computer science is based around universal Turing machines (UTMs): abstract machines able to execute all possible algorithms. Modern digital computers are physical embodiments of classical UTMs. For the most important class of problem in computer science, non-deterministic polynomial complete problems, non-deterministic UTMs (NUTMs) are theoretically exponentially faster than both classical UTMs and quantum mechanical UTMs (QUTMs). However, no attempt has previously been made to build an NUTM, and their construction has been regarded as impossible. Here, we demonstrate the first physical design of an NUTM. This design is based on Thue string rewriting systems, and thereby avoids the limitations of most previous DNA computing schemes: all the computation is local (simple edits to strings) so there is no need for communication, and there is no need to order operations. The design exploits DNA's ability to replicate to execute an exponential number of computational paths in P time. Each Thue rewriting step is embodied in a DNA edit implemented using a novel combination of polymerase chain reactions and site-directed mutagenesis. We demonstrate that the design works using both computational modelling and <i>in vitro</i> molecular biology experimentation: the design is thermodynamically favourable, microprogramming can be used to encode arbitrary Thue rules, all classes of Thue rule can be implemented, and non-deterministic rule implementation. In an NUTM, the resource limitation is space, which contrasts with classical UTMs and QUTMs where it is time. This fundamental difference enables an NUTM to trade space for time, which is significant for both theoretical computer science and physics. It is also of practical importance, for to quote Richard Feynman 'there's plenty of room at the bottom'. This means that a desktop DNA NUTM could potentially utilize more processors than all the electronic computers in the world combined, and thereby outperform the world's current fastest supercomputer, while consuming a tiny fraction of its energy.

Item Type: Article
Uncontrolled Keywords: non-deterministic universal Turing machine, DNA computing, complexity theory
Divisions: Faculty of Health and Life Sciences
Faculty of Health and Life Sciences > Institute of Systems, Molecular and Integrative Biology
Depositing User: Symplectic Admin
Date Deposited: 30 Apr 2024 10:43
Last Modified: 30 Apr 2024 10:43
DOI: 10.1098/rsif.2016.0990
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3180683