Quantum Algorithmic Readout in Multi-Ion Clocks

TL;DR

This paper introduces a quantum algorithmic readout method for multi-ion optical clocks that significantly reduces the overhead in quantum state transfer, enabling more efficient and scalable detection of clock signals.

Contribution

The authors present a novel quantum algorithmic readout technique with logarithmic overhead, implementable with a single multi-species quantum gate, improving upon existing linear overhead methods.

Findings

Overhead scales logarithmically with the number of ions

Implementation demonstrated with Aluminum and Calcium ion crystal

Single multi-species quantum gate suffices for readout

Abstract

Optical clocks based on ensembles of trapped ions offer the perspective of record frequency uncertainty with good short-term stability. Most suitable atomic species lack closed transitions for fast detection such that the clock signal has to be read out indirectly through transferring the quantum state of clock ions to co-trapped logic ions by means of quantum logic operations. For ensembles of clock ions existing methods for quantum logic readout require a linear overhead in either time or the number of logic ions. Here we report a quantum algorithmic readout whose overhead scales logarithmically with the number of clock ions in both of these respects. We show that the readout algorithm can be implemented with a single application of a multi-species quantum gate, which we describe in detail for a crystal of Aluminum and Calcium ions.