Preserving quantum coherence using optimized open-loop control techniques

We describe experimental and theoretical studies of open-loop quantum control techniques known as dynamical decoupling (DD) for the suppression of decoherence-induced errors in quantum systems. Our experiments on trapped atomic ion qubits demonstrate that it is possible to optimize the construction of DD sequences for a given noise power spectral density. Studies of novel sequences derived analytically or through numerical optimization - while maintaining fixed control resources - demonstrate large gains in our ability to preserve quantum coherence in arbitrary noise environments. (C) 2009 Optical Society of America