Dissipative preparation of W states in trapped ion systems

TL;DR

This paper proposes dissipative protocols for preparing W states in three trapped-ion qubits using sympathetic cooling and interference, achieving high fidelity in about 1 ms, with robustness against typical experimental errors.

Contribution

It introduces a novel dissipative scheme utilizing sympathetic cooling and interference to generate W states in trapped ions, avoiding complex timescale hierarchies.

Findings

Estimated fidelity of ~98% in typical experiments

Preparation time around 1 ms

Robustness against thermal motion and calibration errors

Abstract

We present protocols for dissipative entanglement of three trapped-ion qubits and discuss a scheme that uses sympathetic cooling as the dissipation mechanism. This scheme relies on tailored destructive interference to generate any one of six entangled W states in a three-ion qubit space. Using a beryllium-magnesium ion crystal as an example system, we theoretically investigate the protocol's performance and the effects of likely error sources, including thermal secular motion of the ion crystal, calibration imperfections, and spontaneous photon scattering. We estimate that a fidelity of $\sim$ 98 % may be achieved in typical trapped ion experiments with $\sim$ 1 ms interaction time. These protocols avoid timescale hierarchies for faster preparation of entangled states.