Arbitrarily Accurate Dynamical Control in Open Quantum Systems

in open quantum systems in such a way that decoherence is perturbatively compensated for

to a desired (in principle arbitrarily high) level of accuracy, which depends only on the strength of the

relevant errors and the achievable rate of control modulation. ... 
As the gap between theory and implementations shrinks, and a growing experimental effort is devoted to robust

manipulation of quantum states, it is imperative that realistic constraints be accommodated from the outset in dynamical

Quantum Error Correction design. ... A Dynamically Corrected Gate may be viewed as a composite quantum gate

constructed from individual (‘‘primitive’’) building blocks whose errors combine nonlinearly to achieve a substantially

smaller net error ... From a practical standpoint, concatenated DCGs offer the first systematic feedback-free framework

for designing quantum gates which can achieve the arbitrarily high levels of protection against decoherence demanded

by high-fidelity quantum control, and, in particular, Quantum Information Processing."

PRL 104, 090501 (2010) PHYSICAL REVIEW LETTERS week ending 5 MARCH 2010

1Department of Physics and Astronomy, Dartmouth College, 6127 Wilder Laboratory, Hanover, New Hampshire 03755, USA

2Departments of Chemistry, Electrical Engineering, and Physics, and Center for Quantum Information Science & Technology,

University of Southern California, Los Angeles, California 90089, USA

(Received 14 August 2009; revised manuscript received 30 October 2009; published 4 March 2010)