What the Heck is Reversible Computing anyway?
Reversible computing, in a general sense, means computing using reversible operations, that is, operations that can be easily and exactly reversed, or undone. In technical terms, a reversible operation performs a bijective transformation of its local configuration space. When this kind of reversibility is maintained at the lowest level, in the physical mechanisms of operation of our bit-devices (such as transistors), it avoids dissipating the energy that is associated with the bits of information that are being manipulated. This can help to reduce the overall energy dissipation of computations, which can in turn increase battery life or processing speed in heat-limited systems. By about 2050 (perhaps sooner), nearly all computing will be heat-limited, as bit energies approach the absolute thermodynamic lower bound of kT ln 2, where only one bit’s worth of physical information (physical entropy) is used to encode each logical bit. Reversible computing is a necessity in order to further
