A discussion about LNG Experiment: Irreversible or Reversible Generation of the Or Logic Gate?

In a recent paper M. Lopez-Suarez, I. Neri, and L. Gammaitoni (LNG) present a concrete realization of the Boolean Or irreversible gate, but contrary to the standard Landauer principle, with an arbitrary small dissipation of energy. A Popperian good falsification! In this paper we discuss a theoretical description of the LNG gate which is indeed a 3in/3out self–reversible realization of the involved Or gate, satisfying in this way the Landauer principle of no dispersion of energy, contrary to the LNG conclusions. The different point of view is due to a different interpretation of the two outputs corresponding to the inputs 10 and 01, which are considered by LNG indistinguishable so producing a non reversible realization of the gate. On the contrary, we consider these outputs intrinsically, so to speak in line of principle, distinguishable inside the our discussed 3in/3out self-reversible CL gate. In particular, by suitable normalization functions, the experimental results obtained by the LNG device can give rise by the “Inputs-Ancilla-Garbage-Output” procedure to obtain the Or and the And gate using the self-reversible CL gate and the Toffoli gate, respectively. Finally, by other suitable procedures on the 3in/3out self-reversible CL gate it is possible to obtain also the other two logic gates Xor and Nand.