Quantum State Engineering

Howard M. Wiseman, Susanne F. Yelin, Michael M. Kash +3 more

S. L. Wu

We apply the time-dependent decoherence-free subspace theory to a Markovian open quantum system in order to present a proposal for a quantum-state engineering program. By quantifying the purity of the quantum state, we verify that the quantum-state engineering process designed via our method is completely unitary within any total engineering time. Even though the controls on the open quantum system are not perfect, the asymptotic purity is still robust. Owing to its ability to completely resist decoherence and the lack of restraint in terms of the total engineering time, our proposal is suitable for multitask quantum-state engineering program. Therefore, this proposal is not only useful for achieving the quantum-state engineering program experimentally, it also helps us build both a quantum simulation and quantum information equipment in reality.

Chao Shen, L-M Duan

Verifying correlations within a quantum state is an important task in quantum state engineering, while realistic detectors with imperfect efficiency usually introduce errors into the detection results. With these detection errors, genuine multi-partite entanglement can be invisible. In this paper, we propose a simple method for correcting arbitrary uncorrelated detection errors. The method is based on the processing of data from repetitive experiments and can correct detection errors of any magnitude as long as the error magnitude is calibrated. The method is illustrated with its application in the detection of multi-partite entanglement from quantum state engineering.

Georgios M. Nikolopoulos, Igor Jex

Andrea Conti, Andrea Giani, Moe Z. Win