Quantum Information Processing, Vol. 6, No. 1, February 2007 (© 2007)
Non-Markovian Quantum Error Deterrence by
Dynamical Decoupling in a General Environment
and B. L. Hu
Received May 22, 2006; accepted June 14, 2006; Published online January 9, 2007
A dynamical decoupling(DD) scheme for the prevention of errors in the non-
Markovian (usually corresponding to low temperature, short time, and strong
coupling) regimes suitable for qubits constructed out of a multilevel structure is
studied. We use the effective spin-boson model (ESBM) introduced recently [K.
Shiokawa and B. L. Hu, Phys. Rev. A70, 062106 (2004)] as a low tempera-
ture limit of the quantum Brownian oscillator model, where one can obtain exact
solutions for a general environment with colored noises. In our decoupling scheme,
a train of pairs of strong pulses are used to evolve the interaction Hamiltonian
instantaneously. Using this scheme we show that the dynamical decoupling method
can suppress 1/ f noise with slower and hence more accessible pulses than previ-
ously studied, but it still fails to decouple super-Ohmic types of environments.
KEY WORDS: decoherence; open quantum systems; quantum computation;
quantum error correction; dynamical decoupling; protection against decoherence.
PACS: 03.65.Yz; 03.67.Lx; 03.67.Pp.
In quantum information science, quantum coherence and entangle-
ment are used as essential resources for efﬁcient information processing.
Since the interaction of a system with its environment can destruct the
coherence and destroy the entanglement, it is regarded as the most seri-
ous obstacle in the realistic implementation of quantum information pro-
Fast Time, Low Temperature, Strong Field Challenges: In our previous
we introduced an Effective Spin-Boson Model (ESBM), obtained
Department of Physics, University of Maryland, College Park, MD 20742, USA.
Institute of Physical and Chemical Research (RIKEN), Wako-shi 351-0198, Japan; hub@
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1570-0755/07/0200-0055/0 © 2007 Springer Science+Business Media, LLC