When: Thursday 30 November at 14.00
Where: Robert Hooke/Teams Online
Speaker: Jonathan Pritchard – Strathclyde University
Hosted by: Silvia Bergamini
Quantum computation offers a revolutionary approach to how information is processed, offering new applications in material design, quantum chemistry and speed up of real-world optimisation problems, however a large number of qubits are required to obtain quantum advantage over classical hardware. Neutral atoms are an excellent candidate for practical quantum computing, enabling large numbers of identical qubits to be cooled and trapped, overcoming major barriers to scaling experienced by competing architectures. A crucial ingredient for quantum computing is the ability to perform controlled two-qubit gate operations, for which the strong, long-range dipole-dipole interaction between Rydberg atoms can be exploited to implement deterministic gate operations between atoms within a radius of R < 10 μm.
We present progress towards a new experimental platform for quantum computation at the University of Strathclyde, supported by the EPSRC Prosperity Partnership SQuAre with M Squared Lasers Ltd., based on reconfigurable atom arrays of up to 225 Cs atoms. We demonstrate high fidelity single qubit gate operations with errors below the threshold for fault tolerance using a non-destructive readout technique , along with work towards simultaneous trapping of arrays of ground and Rydberg states as the first step to creating a scalable architecture for quantum computing. These results pave the way towards performing high-fidelity two qubit and multi-qubit gate operations using a novel adiabatic rapid passage protocol  developed at Strathclyde, as well as exploring applications of the neutral atom system to solving classical optimisation problems.
 B. Nikolov et al., arXiv:2301.10510 (2023)
 G. Pelegri et al., Quantum Sci. Technol. 7, 045020 (2022)
Jonathan Pritchard is a Reader and RAEng Senior Research Fellow leading work developing neutral atom quantum computing within the Experimental Quantum Optics and Photonics group. Through leadership of SQuAre, an EPSRC Prosperity Partnership with M Squared Lasers, his team have developed the UK’s first scalable platform for neutral atom quantum computing, including developing new protocols for high fidelity multi-qubit gates and demonstrating single-qubit gate operations below the threshold for fault tolerance on arrays of up to 225 qubits. This work forms the underpinning technology for Maxwell, a commercial neutral atom platform developed by M Squared Lasers. As part of a new RAEng Fellowship we are now working to explore routes to fault-tolerant quantum computing by developing a cryogenic dual-species platform for implementing quantum error correction.
Dr. Pritchard obtained his PhD at the University of Durham performing pioneering experiments in the field of Rydberg quantum optics under the supervision of Stuart Adams including the first demonstration of a a new cooperative optical non-linearity arising from dipole-dipole interactions between Rydberg atoms, using electromagnetically induced transparency to convert the strong atomic interactions onto the optical field at the single photon level. He then spent time working in the group of Erling Riis at Strathclyde University developing inductively coupled ring traps for atom interferometry before moving to UW-Madison to develop hybrid systems coupling Rydberg atoms to superconducting circuits in the group of Mark Saffman. In 2015 he was awarded an EPSRC Quantum Technology Fellowship to start his own research group at the University of Strathclyde to develop neutral atom quantum computing platforms, in addition to activities exploring precision sensing using Rydberg atoms and quantum LIDAR.