Steps Toward Fault-Tolerant Quantum Computing with 2D and 3D Superconducting Qubits

John P. Preskill

Na Li, Yu-Huai Li, Dao-Jin Fan +7 more

Cornelis Christiaan Bultink, René Vollmer, Nandini Muthusubramanian +4 more

Héctor Bombín

I present a fault-tolerant quantum computing method for 2D architectures that is particularly appealing for photonic qubits. It relies on a crossover of techniques from topological stabilizer codes and measurement based quantum computation. In particular, it is based on 3D color codes and their transversal operations.

Shiro Kawabata

Superconducting quantum circuits are one of the promising platforms for fault-tolerant universal quantum computers (FTQCs) and quantum annealing machines. We will report our recent activities on integration technology for large-scale superconducting quantum circuits, including 3D integration, fabrication, SPICE simulation, and superconducting control circuits. In addition, theoretical studies on superconducting bosonic qubits and quantum algorithm for FTQC will be presented.

Friederike Butt, Lars Esser, Markus Müller

Practical large-scale quantum computation requires both efficient error correction and robust implementation of logical operations. Three-dimensional (3D) color codes are a promising candidate for fault-tolerant quantum computation due to their transversal non-Clifford gates, but efficient decoding remains challenging. In this work, we extend previous decoders for two-dimensional color codes [1], which are based on the restriction of the decoding problem to a subset of the qubit lattice, to three dimensions. Including boundaries of 3D color codes, we demonstrate that the 3D restriction decoder achieves optimal scaling of the logical error rate and a threshold value of 1.55(6)% for code-capacity bit- and phase-flip noise, which is almost a factor of two higher than previously reported for this family of codes [2, 3]. We furthermore present qCodePlot3D, a Python package for visualizing 2D and 3D color codes, error configurations, and decoding paths, which supports the development and analysis of such decoders. These advancements contribute to making 3D color codes a more practical option for exploring fault-tolerant quantum computation.