Simulation of reversible molecular mechanical logic gates and circuits

Abstract

Landauer's principle places a fundamental lower limit on the work required to perform a logically irreversible operation. Logically reversible gates provide a way to avoid these work costs, and also simplify the task of making the computation as a whole thermodynamically reversible. The inherent reversibility of mechanical logic gates would make them good candidates for the design of practical logically reversible computing systems if not for the relatively large size and mass of such systems. In this paper, we outline the design and simulation of reversible molecular mechanical logic gates that come close to the limits of thermodynamic reversibility even under the effects of thermal noise, and outline associated circuit components from which arbitrary combinatorial reversible circuits can be constructed and simulated. We demonstrate that isolated components can be operated in a thermodynamically reversible manner, and explore the complexities of combining components to implement more complex computations. Finally, we demonstrate a method to construct arbitrarily large reversible combinatorial circuits using multiple external controls and signal boosters with a working half-adder circuit.

Signal Propagation in Resettable Mechanical Logic

“…Mechanical bi-stability mimics binary digital states and the requisite energy well equivalence ensures logic performs the same for both forward and reverse signals. The bene ts of mechanical logic are magni ed at smaller scales 23 , where signal pulses of su cient energy are more easily accessible or can be designed into miniature unpowered structures. We identify rst law limits to signal propagation through bistable elements as well as AND gates and link the scale-independent parameters to simulated and measured performance limitations for logical operations.…”