Individual control and readout of qubits in a sub-diffraction volume

Eric Bersin,Michael Walsh,Tim Schröder,Dirk Englund,Matthew E Trusheim,Sara L Mouradian

doi:10.1038/s41534-019-0154-y

Eric Bersin, Michael Walsh + Show 4 more

Open Access

https://doi.org/10.1038/s41534-019-0154-y

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Abstract

Medium-scale ensembles of coupled qubits offer a platform for near-term quantum technologies as well as studies of many-body physics. A central challenge for coherent control of such systems is the ability to measure individual quantum states without disturbing nearby qubits. Here, we demonstrate the measurement of individual qubit states in a sub-diffraction cluster by selectively exciting spectrally distinguishable nitrogen vacancy centers. We perform super-resolution localization of single centers with nanometer spatial resolution, as well as individual control and readout of spin populations. These measurements indicate a readout-induced crosstalk on non-addressed qubits below 4 × 10−2. This approach opens the door to high-speed control and measurement of qubit registers in mesoscopic spin clusters, with applications ranging from entanglement-enhanced sensors to error-corrected qubit registers to multiplexed quantum repeater nodes.

Highlights

We investigate this approach to multi-qubit readout in a Type IIa polycrystalline diamond (PCD)
Despite the high strain of the PCD,[24] its low nitrogen content allows for nitrogen vacancy (NV) with coherence times exceeding 200 μs at room temperature
The histogram of the NV optical transitions (Fig. 1d) indicates an inhomogeneous distribution with standard deviation of 294 GHz, nearly five times broader than what we measure in single-crystal diamond (SCD) samples

Summary

Introduction

Current super-resolution techniques[19,20] can reach this resolution, but are destructive to the states of nearby qubits, precluding their use for generalized quantum control

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Results

Conclusion