Superconducting Quantum Computing with Real-time Feedforward Contro

by Yongxin Son (ETHZ, ETHZ-PSI QHub)

Wednesday 26 Nov 2025, 10:00 → 11:00 Europe/Zurich

ODRA/111

Real-time feedforward control enables quantum computations that surpass the capabilities of purely unitary gate sequences. In this talk, we present our recent progress on implementing real-time feedforward control in superconducting quantum circuits. We first introduce the hardware architecture designed to support fast, measurement-conditioned operations. Using this platform, we realize a quantum fan-out gate whose circuit depth remains constant independent of the number of output qubits [1], providing a practical method for reducing the depth of algorithms such as the quantum Fourier transform and Shor’s algorithm. We then describe our demonstration of a measurement-based blind quantum computing protocol [2] on a multi-chip superconducting processor comprising two flip-chip-bonded modules, one acting as a server and the other as a client. By adaptively measuring an entangled resource state supplied by the server, the client can perform universal quantum computation without revealing their algorithm or result. These results highlight the power of integrated classical–quantum co-processing and demonstrate the practical utility of real-time feedforward control on NISQ devices.

 [1] Y. Song, et al., Phys. Rev. Applied 24, 024068 (2025)

[2] Y. Song, et al., in preparation