Quantum Information Processing, Vol. 3, Nos. 1–5, October 2004 (© 2004)
Optically Driven Quantum Computing Devices Based
on Semiconductor Quantum Dots
and L. J. Sham
Received February 10, 2004; accepted April 12, 2004
This paper concerns optically driven quantum logic devices based on semiconduc-
tor quantum dots. It provides a brief review of recent theoretical and experimental
progress towards building such devices and a description of a possible direction of
further research. We consider both the exciton and the electron spin as a poten-
tial qubit. Quantum dot fabrication and single dot spectroscopy studies are brieﬂy
discussed followed by a description of experimental demonstrations of basic quan-
tum logic operations. A scheme for a scalable quantum computer based on optical
control of electron spins localized in quantum dots is described in detail. Impor-
tant lessons as well as challenges for future research are summarized.
KEY WORDS: Quantum computing; quantum entanglement; semiconductor
quantum dots; ultrafast optical spectroscopy.
PACS: 78.67.Hc; 42.50.Md; 03.67.Lx; 42.50.Hz.
Semiconductor quantum dot (QD) studies have evolved from ensembles to
single and coupled dots, opening up the possibility of building quantum
devices based on the existing infrastructure for quantum optoelectronic
semiconductor fabrication. It is believed that these dots may be used
as the basic building blocks for future quantum information processing
devices. The focus of this paper is on building optically driven quantum
logic devices based on semiconductor QDs. We aim to provide a simple
FOCUS, Harrison M. Randall Laboratory of Physics, The University of Michigan, Ann
Arbor, MI 48109-1120.
Naval Research Laboratory, Washington, DC 20375-5347.
Department of Physics, University of California, San Diego, La Jolla, CA 92093-0319.
To whom correspondence should be addressed. E-mail: email@example.com
1570-0755/04/1000-0147/0 © 2004 Springer Science+Business Media, Inc.