Quantum gates using spin states of triple quantum dot

We present a new model of quantum gates using electron spins of triplely co upled quantum dots, By using the energy selectivity of both photon-assisted tunneling and spin rotation of electrons, logic gates are realized by stat ic and rotational magnetic field and resonant optical pulses. We used what we call a "tunneling qubit", which realized the switching of interaction be tween quantum bits. Possibility of the extension to many-qubit-system is al so discussed. (C) 2001 Elsevier Science B.V. All rights reserved.