Fuel Efficient Computation in Passive Self-Assembly

TL;DR

This paper demonstrates that passive tile self-assembly can perform universal computation in a fuel and space-efficient manner using negative interactions and limited glue types, advancing the theoretical understanding of self-assembly models.

Contribution

It introduces the first passive tile self-assembly system that is both space and fuel-efficient, utilizing negative interactions and limited glue types for universal computation.

Findings

Achieves universal computation with bounded tiles per step.

Demonstrates space efficiency in passive self-assembly.

Uses negative interactions to enhance fuel efficiency.

Abstract

In this paper we show that passive self-assembly in the context of the tile self-assembly model is capable of performing fuel efficient, universal computation. The tile self-assembly model is a premiere model of self-assembly in which particles are modeled by four-sided squares with glue types assigned to each tile edge. The assembly process is driven by positive and negative force interactions between glue types, allowing for tile assemblies floating in the plane to combine and break apart over time. We refer to this type of assembly model as passive in that the constituent parts remain unchanged throughout the assembly process regardless of their interactions. A computationally universal system is said to be fuel efficient if the number of tiles used up per computation step is bounded by a constant. Work within this model has shown how fuel guzzling tile systems can perform universal computation with only positive strength glue interactions. Recent work has introduced space-efficient, fuel-guzzling universal computation with the addition of negative glue interactions and the use of a powerful non-diagonal class of glue interactions. Other recent work has shown how to achieve fuel efficient computation within active tile self-assembly. In this paper we utilize negative interactions in the tile self-assembly model to achieve the first computationally universal passive tile self-assembly system that is both space and fuel-efficient. In addition, we achieve this result using a limited diagonal class of glue interactions.