arXiv:quant-ph/9912036 · Japanese Journal of Applied Physics

Quantum Computer Using Coupled-Quantum-Dot Molecules

Nan-Jian Wu, Masurao Kamada, Akiko Natori, Hitoshi Yasunaga

Published Jul 1, 2000• 16 citations

Abstract

We propose a method for implementing a quantum computer using artificial molecules. The artificial molecule consists of two coupled quantum dots stacked along the z direction and one single electron. One-qubit and two-qubit gates are constructed by one molecule and two coupled molecules, respectively. The ground state and the first excited state of the molecule are used to encode the |0> and |1> states of a qubit. The qubit is manipulated by a resonant electromagnetic wave that is applied directly to the qubit through a microstrip line. The coupling between two qubits in a quantum-controlled NOT gate is switched on (off) by floating (grounding) the metal film electrodes. We study the operations of the gates using a box-shaped quantum dot model and numerically solving a time-dependent Schrödinger equation, and demonstrate that the quantum gates can perform quantum computations. The operating speed of the gates is about one operation per 4 ps. The reading operation of the output of the quantum computer can be performed by detecting the polarization of the qubits.

DOI: 10.1143/jjap.39.4642

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