Single-electron logic

Previously, the dipole-dipole interaction between the two qubits through magnetic dipoles (nuclear spins in an external magnetic field) was seen through NMR logic. Qubits can also be seen to interact through their electric dipoles (single-electron quantum dots). Mathematically the two cases are identical [109]. While the subjects of this subsection are not molecules as such, the relatively small size of quantum dots justifies their brief discussion here. 

This section on single electron ionization to form cation radicals is logically concluded by a brief discussion of the possibility of ionization to form dications and of their chemistry. Though quantitation is absent, there are three pieces of indirect data that relate to this latter class of cations. The first is the existence and the high stabilityof the pyramidal carbocation, [C(Me)]6 (41). This species may be viewed as formally the dication of hexamethylbenzvalene where the five-fold symmetry in the dication is thwarted by Jahn-Teller effects for the neutral and radical cation forms. No coproportionation reaction of this dication and any neutral benzvalene has been reported to our knowledge. 

Fig. I Truth tables and physical electronic representations of the four single-input logic gates PASS 0, YES, NOT. and PASS 1.

We propose a nuclear spin quantum computer based on magnetic resonance force microscopy (MRFM). It is shown that a MRFM single-electron spin measurement provides three essential requirements for quantum computation in solids (a) preparation of the ground-state, (b) one- and two-qubit quantum logic gates, and (c) a measurement of the final state. — G.P. Berman, G.D. Doolen, RC. Hammel, V.L Tsifrinovich [Rhys. Rev. B 61 (2000) 14694]... 

A variety of possible applications are briefly discussed including the proposed use of nanotubes as the core elements of electronic devices including field-effect transistors, single-electron transistors, rectifying diodes, and logic... 

Keywords Intramolecular kirchhoff laws Molecular electronics Molecular logic gates Single molecule electronic circuits Quantum hamiltonian computing... 

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