Preparation of entangled states through Hilbert space engineering
Yiheng Lin, John P. Gaebler, Florentin Reiter, Ting Rei Tan, Ryan S. Bowler, Yong Wan, Adam C. Keith, Emanuel H. Knill, Kevin J. Coakley, Dietrich G. Leibfried, David J. Wineland, Scott C. Glancy
Entangled states are a crucial resource for quantum-based technologies such as quantum computers and quantum communication systems. Exploring new methods for entanglement generation is important for diversifying and eventually improving current approaches. Here, we create entanglement in atomic ions by applying laser fields to constrain evolution to a restricted number of states, in an approach that has become known as quantum Zeno dynamics. With two trapped 9Be+ ions, we obtain Bell state fidelities 0:993+2-3; with three ions, a W-state fidelity of 0:910+4-5 . Compared to other methods of producing entanglement in trapped ions, this procedure is relatively insensitive to certain imperfections such as fluctuations in laser intensity and frequency, and ion-motion frequencies.