Quantum Simulation and Quantum Computation with Strings of Trapped Ca⁺ Ions

The state-of-the-art of the Innsbruck trapped-ion quantum computer is briefly reviewed. We present an overview on the available quantum toolbox and discuss the scalability of the approach. With 20-50 fully controlled ion qubits we perform quantum simulations investigating quantum transport [1] and emerging hydrodynamics features [2]. Employing the quantum toolbox for entanglement-enhanced Ramsey interferometry, we find optimal parameters for quantum metrology [3]. Quantum computers can be protected from noise by encoding the logical quantum information redundantly into multiple qubits using error-correcting codes. Manipulating logical quantum states by imperfect operations requires that all operations on the quantum register obey a fault-tolerant circuit design to avoid spreading uncontrolled errors. We demonstrate a fault-tolerant universal set of gates on two logical qubits in the trapped-ion quantum computer [4].





[1] C. Maier et al., Phys. Rev. Lett. 122, 050501 (2019)

[2] M. K. Joshi et al., arXiv:2107.00033 (2021)

[3] C. D. Marciniak et al., arXiv:2107.01860 (2021)

[4] L. Postler et al., arXiv:2111.12654 (2021)