Abstract: A single-chain twenty-qubit quantum chip was designedWe design a single chain twenty qubits chip by using frequency adjustable transmon structure. We performed basic characterization experiments on all qubits using a customized low-temperature environment control system and low-temperature coaxial cable components, which have attained chieving a maximum energy decoherence time T₁ of 31.3 μs and a phase decoherence time T₂* of 22.8 μs among all qubits. An average fidelity of 99.85% for of single-qubit gates was gained as determined by random benchmark testing. The two-qubit Controlled-ZZ gate calibration was also achieved, with a fidelity of 97.5% measured through quantum process tomography. Finally, we demonstrated a quantum dynamics simulation algorithm based on the operation of single-qubits gates and double-qubits gates, successfully observing the dynamical evolution of the Ising model.

Key words: quantum computing, superconducting qubit, quantum algorithm