Rydberg Atom Quantum Technologies

Welcome to the Rydberg Atom Quantum Technologies team lead by Dr. Jonathan Pritchard, an RAEng Senior Research Fellow at the University of Strathclyde.

Overview

Rydberg atoms are atoms excited to extremely large principal quantum numbers resulting in giant atoms offering exaggerated properties including enormous electric-dipole moments in the microwave frequency range and strong, tuneable long-range interactions. Our research is focused on developing new quantum technologies that exploit these properties to develop scalable platforms for quantum computation and optimisation, and atomic gas sensors for precision microwave field detection and imaging.

Please contact jonathan.pritchard@strath.ac.uk if you are interested in working in within one of our research areas – we have both PhD and PDRA Positions Currently Available across both projects developing neutral atom quantum computers based on scalable arrays of neutral atoms.

Research

Quantum Error Correction (QuERy)
This project, supported by a Royal Academy of Engineering Senior Research Fellowship and M Squared Lasers, seeks to develop a new experiment focused on creating dual-species arrays of Cs and Rb for quantum error correction. This is integrated within a 4K closed-cycle cryostat to obtain extended trap lifetime for scaling to large numbers of qubits, and will focus on exploiting long-range dipole interactions between Rydberg states of each species to enable mid-circuit, non-destructive readout and generation of topologically protected logical qubits as a route towards fault tolerant digital quantum computing.

Quantum Error Correction (QuERy)
Scalable Qubit Arrays (SQuAre)
This project is an EPSRC Prosperity Partnership with M Squared Lasers that aims to develop a new platform for quantum computing based on scalable arrays of neutral atoms that is able to overcome the challenges to scaling of competing technologies. We will develop new hardware to cool and trap arrays of over 100 qubits that will be used to perform both analogue and digital quantum simulation by exploiting the strong long-range interactions of highly excited Rydberg atoms. Together with the quantum software team lead by Prof. Andrew Daley, we will design new analogue and digital algorithms tailored for the neutral-atom platform to target industrially-relevant computation and optimisation problems.

Scalable Qubit Arrays (SQuAre)
ARC:Alkali Rydberg Calculator
An open-source python library for calculating properties of Alkali Rydberg atoms developed with Nikola Sibalic, Charles Adams and Kevin Weatherill at JQC in Durham. Full details on the arXiv:1612.05529 - download source from GitHub.


ARC:Alkali Rydberg Calculator
Quantum Lidar
In collaboration with the theory team lead by Prof. John Jeffers and supported by DSTL, we are developing new approaches to quantum enhanced LIDAR by creating a compact optical frequency comb source for pumping birefringent optical fibres and exploring a new log-likelihood metric to perform quantum enhanced stand-off detection and range-finding.

Quantum Lidar

Latest News

Demonstration of quantum-enhanced rangefinding robust against classical jamming
We utilise a correlated pair-source to perform target detection and range-finding to demonstrate the resilience of quantum-enhanced lidar to classical jamming arXiv:2307.10794.
Demonstration of quantum-enhanced rangefinding robust against classical jamming
Randomised benchmarking and non-destructive readout
We have demonstrated high-fidelity randomised benchmarking of single qubit microwave gates across an array of 225 atoms, and non-destructive readout of up to 49 atoms. We achieved an average gate error of 8×10-5 which is below the threshold for fault tolerant operations, highlighting the viability of neutral atoms for scalable computing. For more details see our paper Phys. Rev. Lett. 131, 03602 (2023) [arXiv].
Randomised benchmarking and non-destructive readout
Two-Qubit EIT Gate Protocol
We have demonstrated the UK’s first neutral atom two-qubit gate using a novel protocol based on electromagnetically induced transparency originally proposed back in 2008. We achieve a corrected CNOT gate fidelity of 0.82(6), mainly limited by available laser power. For more details see Phys. Rev. Lett. 129, 200501 (2022).
Two-Qubit EIT Gate Protocol
High-fidelity multi-qubit gate operations
We have developed a robust protocol for implementing high-fidelity multiqubit controlled phase gates (CkZ) on neutral atom qubits coupled to highly excited Rydberg states via adiabatic rapid passage (ARP). We find a CCZ gate with fidelity F > 0.995 for three qubits and CCCZ with F > 0.99 for four qubits is attainable in ∼ 1.8 μs via this protocol. For more details see our paper in QST.
High-fidelity multi-qubit gate operations

Team

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Boyko Nikolov

PhD student

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Dr André de Oliveira

Postdoc

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Dr Daniel Walker

Postdoc

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Dr Jonathan Bass

Postdoc

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Dr Jonathan Pritchard

Reader

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Elliot Diamond-Hitchcock

PhD student

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Mateusz Mrozowski

PhD student

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Paul Ireland

PhD student

Publications

B. Nikolov, E. Diamond-Hitchcock, J. Bass, N. L. R. Spong, J. D. Pritchard, Randomized Benchmarking Using Nondestructive Readout in a Two-Dimensional Atom Array. Physical Review Letters 131, 030602 (2023).

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M. P. Mrozowski, J. Jeffers, J. D. Pritchard, High-efficiency coupled-cavity optical frequency comb generation. Optics Continuum 2, 894 (2023).

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M. P. Mrozowski, R. J. Murchie, J. Jeffers, J. D. Pritchard, Demonstration of quantum-enhanced rangefinding robust against classical jamming. (2023).

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R. J. Murchie, J. D. Pritchard, J. Jeffers, Object detection and rangefinding with quantum states using simple detection. (2023).

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K. McDonnell, L. F. Keary, J. D. Pritchard, Demonstration of a Quantum Gate Using Electromagnetically Induced Transparency. Physical Review Letters 129, 200501 (2022).

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G. Pelegrí, A. J. Daley, J. D. Pritchard, High-fidelity multiqubit Rydberg gates via two-photon adiabatic rapid passage. Quantum Science and Technology 7, 045020 (2022).

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L. F. Keary, J. D. Pritchard, Strong coupling and active cooling in a finite-temperature hybrid atom-cavity system. Physical Review A 105, 013707 (2022).

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A. Chopinaud, J. Pritchard, Optimal State Choice for Rydberg-Atom Microwave Sensors. Physical Review Applied 16, 024008 (2021).

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Y. Chu, J. D. Pritchard, H. Wang, M. Weides, Hybrid quantum devices: Guest editorial. Applied Physics Letters 118, 240401 (2021).

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C. S. Adams, J. D. Pritchard, J. P. Shaffer, Rydberg atom quantum technologies. Journal of Physics B: Atomic, Molecular and Optical Physics 53, 012002 (2020).

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See all

Funding

We acknowledge funding from the following sources:

Previous Projects

Microwave Field Sensing using Rydberg atoms
RF fields in the microwave and terahertz domain are ubiquitous for security and communications, however test equipment requires frequent recalibration and careful understanding of the perturbations caused by the antenna used for measurement. This project, a collaboration between researchers at the University of Strathclyde and Durham University, seeks to develop new all-optical field sensors operating in the microwave and terahertz domain using Rydberg atoms in a thermal vapour to act as microscopic antenna enabling metal-free probing, sub-wavelength imaging resolution and the ability to implement a traceable SI calibration offering superior sensitivity compared to existing technologies. Early results include a careful characterisation of linearity and optimal state choice for precision RF sensing using this approach.

Microwave Field Sensing using Rydberg atoms
Hybrid Quantum Interface

As part of an EPSRC Quantum Technology Fellowship we developed a new experimental apparatus to perform two-qubit operations using individually trapped Cs atoms. Highlights from this work included first demonstrations of single atom imaging using an sCMOS camera, high-fidelity and long-coherence entanglement generation and the first native CNOT gate protocol based on electromagnetically induced transparency. This apparatus has now been rebuilt as part of the Quantum Error Correction using Cryogenic Dual-Species Arrays project which builds on these early milestones and will integrate the system into a 4 K cryostat.

Separately we investigated hybrid approaches to quantum networking by developing optimised NbN resonators at 15 GHz for coupling Rydberg states to superconducting microwave circuits in a 4 K environment in collaboration with the Quantum Devices group at Glasgow University lead by Martin Weides. We have shown theoretically that this system can be used for demonstrations of strong-coupling and active cooling providing Q factors of 105 and above can be achieved.


Hybrid Quantum Interface