Preparation of entangled states through Hilbert space engineering

TL;DR

This paper introduces a novel method for generating entangled states in trapped ions using Hilbert space engineering via quantum Zeno dynamics, achieving high fidelities and robustness against experimental imperfections.

Contribution

The authors demonstrate a new entanglement generation technique in trapped ions employing quantum Zeno dynamics, improving fidelity and robustness over existing methods.

Findings

Bell state fidelity up to 0.990 in two ions

W-state fidelity of 0.910 in three ions

Method shows resilience to laser and motional fluctuations

Abstract

Entangled states are a crucial resource for quantum-based technologies such as quantum computers and quantum communication systems (1,2). 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 the evolution to a restricted number of states, in an approach that has become known as "quantum Zeno dynamics" (3-5). With two trapped $^9\rm{Be}^+$ ions, we obtain Bell state fidelities up to $0.990^{+2}_{-5}$, with three ions, a W-state (6) fidelity of $0.910^{+4}_{-7}$ is obtained. Compared to other methods of producing entanglement in trapped ions, this procedure is relatively insensitive to certain imperfections such as fluctuations in laser intensity, laser frequency, and ion-motion frequencies.