IQM quantum processing units (QPUs) with superconduting qubits

Hsiang-Sheng Ku

Superconducting qubits are one of the most advanced technologies for implementing a quantum processing unit (QPU). At IQM, QPUs based on two distinct topologies are being developed: a mainstream architecture comprising a square lattice of qubits (referred to as "Crystal") and a qubit-resonator system with star topology, in which multiple qubits are coupled to a central resonator (referred to as "Star"). While the Crystal QPU is well-suited for executing typical Noisy Intermediate-Scale Quantum (NISQ) algorithms and quantum error-correcting surface code, the Star QPU can be advantageous for applications that demand one-to-all or even all-to-all connectivity.

This talk will present IQM’s technical choices of fundamental components such as floating tunable transmon couplers and frequency multiplexed readout circuitry, along with system-level and application benchmarks that quantify the performance of the Crystal 20 QPU. In addition, the concept of the operation of the qubit-resonator system is discussed, with benchmark results from Star 6. By combining the advantageous features of Crystal and Satr, we anticipate a promising architecture capable of implementing hardware-efficient quantum error correction codes to build a fault-tolerant superconducting quantum computer.