Realization of modular quantum computers via parametric interactions
Precisely controlled couplings between qubits are vital parts of all quantum information processing. For superconducting qubits, most platforms employ a network of two-body interactions between nearest-neighbor qubits in a two-dimensional lattice, the so-called “surface code” structure. However, longer range and multi-node couplings are very desirable as they reduce the overhead of interactions between distant qubits, and enable new topologies for large-scale quantum computers. In my PhD research, I have been working on realizing such qubit connections via parametric interactions and using them to build modular quantum computers. We have realized two modular machines: a modular quantum state router with all-to-all couplings among 4 modules [1], and a compact 4-qubit quantum module. Both systems are designed with the idea of coupling multiple computational modes to a central Superconducting Nonlinear Asymmetric Inductive eLement (SNAIL) and are fully controlled with 3-wave-mixing parametric interactions. I will present experiment results measured in both systems, including fast all-to-all gates between arbitrary module cavity pairs, high-fidelity single and multi-qubit parametric gates, and inter/intra-module qubit entanglement. The operations demonstrated here can readily be extended to faster and higher-fidelity parametric operations, as well as scaled to support larger networks of modular quantum computers [2].
- C. Zhou, P. Lu, M. Praquin, T.-C. Chien, R. Kaufman, X. Cao, M. Xia, R. Mong, W. Pfaff, D. Pekker, M. Hatridge. A modular quantum computer based on a quantum state router. arXiv:2109.06848 (2021).
- E. McKinney, M. Xia, C. Zhou, P. Lu, M. Hatridge, and A. Jones. Co-designed architectures for modular superconducting quantum computers. To Appear in IEEE Symposium on High Performance Computer Architecture (HPCA) (2023). Available at: arXiv:2205.04387.
