Quantum Information Processing, Vol. 3, Nos. 1–5, October 2004 (© 2004)
Quantum Computing with Trapped Ion Hyperﬁne
B. B. Blinov,
and D. J. Wineland
Received January 30, 2004; accepted March 5, 2004
We discuss the basic aspects of quantum information processing with trapped
ions, including the principles of ion trapping, preparation and detection of hyper-
ﬁne qubits, single-qubit operations and multi-qubit entanglement protocols. Recent
experimental advances and future research directions are outlined.
KEY WORDS: Ion trapping; hyperﬁne qubits; quantum gates; qubit detection;
qubit initialization; entanglement.
PACS: 03.67.Lx, 32.80.Pj, 32.80.Qk, 42.50.Vk.
Trapped atomic ions were ﬁrst proposed as a viable quantum comput-
ing candidate by Cirac and Zoller in 1995.
Almost 10 years later,
the trapped ion system remains one of the few candidates that satis-
ﬁes the general requirements for a quantum computer as outlined by
: (i) a scalable system of well-deﬁned qubits, (ii) a method to
reliably initialize the quantum system, (iii) long coherence times, (iv) exis-
tence of universal gates, and (v) an efﬁcient measurement scheme. Most
of these requirements have been demonstrated experimentally with trapped
ions, and there exist straightforward (albeit technically difﬁcult) paths to
solving the remaining problems.
Experimental approaches in ion trap quantum computing can be
divided by the type of qubit, in terms of the qubit level energy splitting,
FOCUS Center and Department of Physics, University of Michigan Ann Arbor, MI 48109,
USA; e-mail: firstname.lastname@example.org
Time and Frequency Division, National Institute of Standards and Technology Boulder,
CO 80303, USA.
To whom correspondence should be addressed.
1570-0755/04/1000-0045/0 © 2004 Springer Science+Business Media, Inc.