ISSN 10637397, Russian Microelectronics, 2011, Vol. 40, No. 4, pp. 237–244. © Pleiades Publishing, Ltd., 2011.
Original Russian Text © I.I. Beterov, D.B. Tretyakov, V.M. Entin, E.A. Yakshina, I.I. Ryabtsev, P.L.Chapovsky, V.I. Yudin, A.N. Goncharov, A.V. Taychenachev, S.V. Prants,
2011, published in Mikroelektronika, 2011, Vol. 40, No. 4, pp. 256–263
The problem of developing a quantum computer
occupies a specific place in modern science. As opposed
to many important problems that are of interest only for
specialists, the implementation of quantum calculations
may lead to significant progress not only in understand
ing physics, mathematics, or informatics, but also nature
in general. In Yuri Manin’s pioneering work , the
necessity of developing quantum automatons’ theory for
describing the DNA double helix unfolding process is
discussed. Richard Feynman  drew attention to the
problem of computer simulation of quantum phenom
ena: perhaps the best means of carrying out such simula
tions will be a quantum computer .
Let us consider a circuit consisting of
objects, each of which can be in two quantum states.
Such quantum objects are called quantum bits or
qubits, and consist of one system, a quantum register.
Two qubit states correspond to logical zero and one.
Unlike a classical bit, a qubit can exist in the quantum
superposition of states . Conse
quently, the quantum register of
qubits can be in a
coherent superposition of
states and the change of
state of one or more qubits will change all of the states.
Simulation using a classical computer would require
steps for an elementary quantum operation .
Arising this way, the quantum parallelism is the main
practical advantage of quantum computers.
Although the relevance of the quantum computer is
obvious, the question remains whether there is a real
opportunity to create it. The path from the demonstra
tion of individual quantum operations to an operating
quantum computer can be long and difficult. Promis
ing use of a quantum system for experimental imple
mentation of quantum calculations can be estimated
on the basis of the five criteria offered in DiVincenzo’s
papers [5, 6]:
1. A quantum register must consist of a set of
qubits, namely, quantum systems. Single qubits must
be distinguishable. Every qubit’s state must be con
trolled externally. Each must be a twolevel system,
where spontaneous transition to any different quan
tum level is not allowed. In addition, new qubits can be
added to the quantum register if necessary (scaling).
2. Before beginning a calculation, the quantum
register must be initialized. For example, all qubits are
transferred to state
3. The decay time of coherent quantum states
(decoherence) of qubits must be large, at least
larger than the time of one quantum logic operation.
4. During the quantum computation, reversible
unitary quantum logical operations on individual
qubits and on arbitrary pairs of qubits should be car
ried out. The Hadamard transformation
phase gate are examples of such singlequbit
operations. They are described by matrices
Quantum Informatics with Single Atoms
I. I. Beterov
, D. B. Tretyakov
, V. M. Entin
, E. A. Yakshina
, I. I. Ryabtsev
, P. L. Chapovsky
V. I. Yudin
, A. N. Goncharov
, A. V. Taychenachev
, and S. V. Prants
Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, pr. Lavrentieva 13, Novosibirsk,
Institute of Automation and Electrometry, Siberian Branch of Russian Academy of Sciences, pr. Koptyuga 1, Novosibirsk,
Institute of Laser Physics, Siberian Branch, Russian Academy of Sciences, pr. Lavrentieva 13/3, Novosibirsk, 630090 Russia
Novosibirsk State University, ul. Pirogova ul. 2, Novosibirsk, 630090 Russia
Pacific Oceanological Institute, Far Eastern Branch, Russian Academy of Sciences, ul. Baltiyskaya 43, Vladivostok,
email: email@example.com; firstname.lastname@example.org
Received July 1, 2010
—Current status of the research on the use of single neutral atoms, captured in optical traps, as a
quantum computer’s qubits, is briefly reviewed. The specifics of qubits based on cold atoms and t quantum
logical operations via dipole interaction by shorttime laser excitation in a Rydberg state are discussed. The
latest experimental results of the observation of dipole interaction between two Rydberg atoms and of atoms’
entangled states in a ground state are given.
QUANTUM INFORMATION SCIENCE