Because these operations are both logically and thermodynamically reversible, energy dissipation can be reduced to extremely low levels. This is the first proposal known to the authors that combines thermodynamic reversibility with the use of single charge carriers. It is important to note that this proposal permits a single electron to switch another single electron, and does not require that many electrons be used to switch one electron. Irreversible operations, when required, can be easily implemented and should have a dissipation approaching the fundamental limit of ln 2 x kT. Introduction Trends in computer hardware are leading toward higher density and lower energy dissipation. The trend towards higher packing density strongly influences energy dissipation.
Conventional circuits perform more poorly.
Even an idealized device which used a one volt power supply and dissipatively discharged a single electron to ground during a switching operation would dissipate one electron volt per switching operation. If each switching operation involves hundreds of electrons then energy dissipation enters the multigigawatt range. Low temperature operation doesn't actually reduce total energy dissipation, it just shifts it from computation to refrigeration. Thermodynamically reversible logic elements, in contrast, can reduce total energy dissipation per logic operation to well below kT. This paper analyzes a proposed thermodynamically reversible single electron logic system. This page is part of the nanotechnology web site.