論文
Chern-number estimation: nearly optimal quantum algorithm and provable quantum speedup
Soichiro Imamura, Shintaro Ae, Kazuki Sakamoto, Ryu Hayakawa, Chusei Kiumi
arXiv:2609.35978
The Chern number is a fundamental invariant characterizing topological phases. We propose a quantum algorithm for Chern-number estimation in a setting where ground-state preparation is available only at a single point in parameter space. We further establish a corresponding complexity lower bound, proving optimality up to polylogarithmic factors. We also show that computing the Chern number is in FBQP and is BQP-hard, while deciding whether the Chern number is zero or one is BQP-complete.
Parallel Hadamard Test
Soichiro Imamura, Synge Todo
arXiv:2607.12344
We propose a parallel Hadamard test that combines multiple expectation-value-estimation tasks into a single circuit type. The method reduces circuit-level overhead for three classes of workloads and may lower both runtime and financial cost in cloud quantum computing.