>PRESENTATION:
Roberto Leporini is researcher at the University of Bergamo. His research work originates in studies on the theory of conservative computing and quantum gates for finite-valued logics, and presently concerns logics from quantum computation and nanotechnologies.

Two possible quantum descriptions of the classical NOT gate are investigated in the framework of the Hilbert space C2: the unitary and the anti-unitary operator realizations. The two cases are distinguished interpreting the unitary NOT as a quantum realization of the classical gate which on a fixed orthogonal pair of unit vectors, realizing once for all the classical bits 0 and 1, produces the required transformations from 0 to 1 and from 1 to 0 (i.e., logical quantum NOT). The anti-unitary NOT is a quantum realization of a gate which acts as a classical NOT on any pair of mutually orthogonal vectors, each of which is a potential realization of the classical bits (i.e., universal quantum NOT).