Scalable quantum processors open up new opportunities for research and development, comparable to the advent of integrated circuits in the past century. The aim of this joint project is the construction and operation of an elementary quantum processor unit based on trapped atomic ions, in collaboration with academic and industrial partners from the University of Mainz, Fraunhofer-Gesellschaft, TOPTICA and AKKA. This platform has qubits with coherence times of several seconds and high quality laser-driven gates. The technological approach pursued in this project combines individual optical addressing on smaller qubit registers with the dynamic configuration of quantum registers by moving, exchanging and regrouping the ions [1]. This creates a scalable solution with high qubit connectivity. It is planned to connect the quantum processor to the Mainz high-performance computer and to make it available to external users as a user facility: First application algorithms can be from the field of quantum chemistry or optimisation.
The focus of the work of our theory group will be on the development of protocols for the characterisation (benchmarking) and new methods for compiling the user-defined algorithms into sequences of available elementary ion-crystal reconfiguration steps and native gate operations. Recently, we developed and implemented together with our experimental colleagues in Mainz a flag-qubit based stabiliser measurement protocol – a key building block for scalable and fault-tolerant quantum error correction [2].
[1] Shuttling-Based Trapped-Ion Quantum Information Processing
V. Kaushal, B. Lekitsch, A. Stahl, J. Hilder, D. Pijn, C. Schmiegelow, A. Bermudez, M. Müller, F. Schmidt-Kaler, U. Poschinger
AVS Quantum Sci. 2, 014101 (2020)
[2] Fault-tolerant parity readout on a shuttling-based trapped-ion quantum computer, J. Hilder, D. Pijn, O. Onishchenko, A. Stahl, M. Orth, B. Lekitsch, A. Rodriguez-Blanco, M. Müller, F. Schmidt-Kaler, U. Poschinger, Physical Review X – in press (arXiv:2107.06368)
