Creation of arbitrary Dicke and NOON states of trapped-ion qubits by global addressing with composite pulses

TL;DR

This paper introduces a fast, scalable method using composite pulses to generate highly entangled states like Dicke and NOON states in trapped-ion qubits, without needing individual ion addressing.

Contribution

The authors develop a technique that efficiently creates entangled states in trapped ions using global resonant pulses, scalable with system size, and applicable beyond the Lamb-Dicke regime.

Findings

Method operates on short time scales

Implementation complexity grows linearly with number of ions

Does not require individual ion addressing

Abstract

We propose a fast and efficient technique to create classes of highly entangled states of trapped ions, such as arbitrary Dicke states and superpositions of them, e.g. NOON states. The ions are initialized in the phonon ground state and are addressed globally with a composite pulse that is resonant with the first motional sideband. The technique operates on comparatively short time scales, as resonant interactions allow one to use the minimum laser pulse area. The number of single pulses from the composite sequence is equal to the number of ions, thus the implementation complexity grows only linearly with the size of the system. The approach does not require individual addressing of the ions in the trap and can be applied both inside and outside the Lamb-Dicke regime.