Quantum Information Processing, Vol. 3, Nos. 1–5, October 2004 (© 2004)
Spin-based Quantum Dot Quantum Computing
Mark A. Eriksson,
Susan N. Coppersmith,
Levente J. Klein,
P. M. Mooney,
J. O. Chu,
and S. J. Koester
Received February 18, 2004; accepted April 28, 2004
The spins of localized electrons in silicon are strong candidates for quantum
information processing because of their extremely long coherence times and the
integrability of Si within the present microelectronics infrastructure. This paper
reviews a strategy for fabricating single electron spin qubits in gated quantum
dots in Si/SiGe heterostructures. We discuss the pros and cons of using silicon,
present recent advances, and outline challenges.
KEY WORDS: Quantum computation; quantum dot; silicon; silicon–germa-
nium; spin; quantum well.
PACS: 03.67.Pp; 03.67.Lx; 85.35.Be; 73.21.La.
The seminal paper by Loss and DiVincenzo
outlined essential compo-
nents of quantum dot quantum computing (QDQC): (1) spin qubits in
single electron dots, (2) qubit initialization by thermalization in a magnetic
ﬁeld, (3) qubit rotations performed using electron spin resonance (ESR),
(4) two-qubit gates enabled by electrostatic control of exchange coupling in
neighboring dots, and (5) readout by spin-charge transduction. Subsequent
theoretical work has shown that two-qubit gates can be sufﬁciently fast
and that these same interactions can be harnessed
for single-qubit rotations,
albeit with some encoding overhead. The
most challenging aspect of scalable QDQC is fast readout: spin-dependent
Physics Department, University of Wisconsin-Madison, Madison, WI 53706 USA.
IBM Research Division T.J. Watson Research Center Yorktown Heights, NY 10598 USA.
1570-0755/04/1000-0133/0 © 2004 Springer Science+Business Media, Inc.