title: Experimental demonstration of delayed-choice decoherence suppression.
abstract: Wheeler's delayed-choice experiment illustrates vividly that the observer plays a central role in quantum physics by demonstrating that complementarity or wave-particle duality can be enforced even after the photon has already entered the interferometer. The delayed-choice quantum eraser experiment further demonstrates that complementarity can be enforced even after detection of a quantum system, elucidating the foundational nature of complementarity in quantum physics. However, the applicability of the delayed-choice method for practical quantum information protocols continues to be an open question. Here, we introduce and experimentally demonstrate the delayed-choice decoherence suppression protocol, in which the decision to suppress decoherence on an entangled two-qubit state is delayed until after the decoherence and even after the detection of a qubit. Our result suggests a new way to tackle Markovian decoherence in a delayed manner, applicable for practical entanglement distribution over a dissipative channel.
authors: Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang 790-784, Korea.
authors: Jong-Chan
authors: JC
authors: Lee
authors: Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang 790-784, Korea.
authors: Hyang-Tag
authors: HT
authors: Lim
authors: Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang 790-784, Korea.
authors: Kang-Hee
authors: KH
authors: Hong
authors: Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang 790-784, Korea.
authors: Youn-Chang
authors: YC
authors: Jeong
authors: 1] QOLS, Blackett Laboratory, Imperial College London, London SW7 2AZ, UK [2] School of Computational Sciences, Korea Institute for Advanced Study, Seoul 130-722, Korea.
authors: M S
authors: MS
authors: Kim
authors: Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang 790-784, Korea.
authors: Yoon-Ho
authors: YH
authors: Kim