Times of Execution of the CCNOT and CCCNOT Quantum Gates in a Quantum Computer based on a Quantum Dots Technology

Abstract

It is considered a quantum computer consisting of a system of quantum dots (electrons) which are described by a Hamiltonian having rotation, inversion, and exchange symmetries. We consider exclusively the cases of both n = 3 and n = 4 quantum dots. In order to neglect their mutual Coulomb-like interactions, the electron dots are allocated very far way one of each other. In quantum dot technologies the figure of merit is the structure of the confinement potential. Thus, a realistic confinement potential of an electron dot which is composed of a very high rectangular potential well of width approximately equal to three orders of magnitude of the electron dot Compton wavelength (one nanometer) is proposed here. In order to verify the consistence of the present approach, the times of execution of the CCNOT and CCCNOT gates are calculated. It is found that in the case of a soft tunneling through the walls of the potential, the times of execution of such a gates are drastically small.