Superconducting Quantum Circuits and Quantum Computation

(Haohua Wang, Yi Yin etc)

Quantum computation is one of the research frontiers of physical science in the 21st century. The implementation of quantum speedup in computational tasks exploits quantum properties such as superposition and entanglement, and the candidate physical systems for achieving quantum computation include photons, ion traps, quantum dots, and superconducting Josephson junctions. Compared with other candidates, the superconducting system has advantages in controllability and scalability, which is promising in scaling up utilizing silicon-based manufacturing technology.

The research group at Zhejiang University focuses on quantum computation and simulation with superconducting Josephson junctions. In cooperation with other domestic institutions, the group has developed high performance multi-qubit superconducting quantum circuits, and has shown advanced experimental skills and made significant progresses in a series of notable experiments, including a quantum simulation experiment where quantum entangled states are constructed to emulate the fractional statistical behavior of anyons in Kitaev spin lattice model. Recently, the group has developed a 10-qubit superconducting quantum circuit in collaboration with IOP, USTC, and FZU, and has deterministically produced the Greenberger-Horne-Zeilinger (GHZ) states with up to 10 qubits. The 10-qubit GHZ state, whose full information was obtained through tomographic measurement, represents the largest entangled state produced so far in solid state architectures. Furthermore, the group has showcased an experiment of preliminarily executing a quantum algorithm for solving linear equations on a 4-qubit superconducting quantum circuit, demonstrating the speedup possibility with quantum parallelism. In recent years, the group has published 10 experimental papers in high impact journals of Nature Communications and Physical Review Letters.