Jun SUZUKI (鈴木淳)

0120200_情報・ネットワーク工学専攻, 0120000_大学院情報理工学研究科, The University of Electro-Communications

Quantum estimation theory | 量子推定理論

quantum information theory | 量子情報理論

ジャーナル論文 - rm_misc: Technical Report

Hybrid Cram\'er-Rao bound for Quantum Bayes-Point Estimation with Nuisance Parameters

by Jun SUZUKI

公開済 10/2025

Preprint arXiv, quant-ph, 2510.16810

ジャーナル論文 - rm_published_papers: Scientific Journal 査読済み

Holevo Cramér-Rao bound: How close can we get without entangling measurements?

by Jun SUZUKI

公開済 30/09/2025

Quantum, 9, 1867 - 1867

In multi-parameter quantum metrology, the resource of entanglement can lead to an increase in efficiency of the estimation process. Entanglement can be used in the state preparation stage, or the measurement stage, or both, to harness this advantage; here we focus on the role of entangling measurements. Specifically, entangling or collective measurements over multiple identical copies of a probe state are known to be superior to measuring each probe individually, but the extent of this improvement is an open problem. It is also known that such entangling measurements, though resource-intensive, are required to attain the ultimate limits in multi-parameter quantum metrology and quantum information processing tasks. In this work we investigate the maximum precision improvement that collective quantum measurements can offer over individual measurements for estimating parameters of qudit states, calling this the 'collective quantum enhancement'. We show that, whereas the maximum enhancement can, in principle, be a factor of for estimating parameters, this bound is not tight for large . Instead, our results prove an enhancement linear in dimension of the qudit is possible using collective measurements and lead us to conjecture that this is the maximum collective quantum enhancement in any local estimation scenario.

ジャーナル論文 - rm_published_papers: International Conference Proceedings 査読済み

Eﬃcient Computation of Bayesian Nagaoka-Hayashi Bound for Quantum Multiparameter Estimation of IID Models

by Jun SUZUKI

公開済 08/2025

Proceedings for 25th Asian Quantum Information Science Conference, P3, 28