Work

Distinct Feedback-Strength Requirements for Quantum-State Ensemble Preparation under Channel-Equivalent Monitoring

Year: 2026

Type: preprint

Abstract: Different measurements of the same environment can preserve the average quantum channel yet change the feedback strength needed to prepare a state ensemble. We establish this distinction for a multiqubit register under complete Pauli monitoring, targeting the uniform ensemble of real-amplitude pure states. With unit detection efficiency, public records, and bounded Hamiltonian feedback, fixed transverse noise requires a minimum peak strength proportional to $ε^{-1}$ at distributional error $ε$. Tangent noise instead admits a construction requiring only $O[\sqrt{\log(1/ε)}]$. At fixed preparation time, we determine the optimum over all allowed feedback policies and derive a geometric lower bound beyond radial symmetry. The separation identifies the measurement realization as part of the control-resource specification for monitored ensemble preparation.

Source: arXiv (Cornell University)

DOI: 10.48550/arxiv.2609.31221

Authors: Huang, Haitao, Zhao, Qinglin, Li, Xiaoyu

Institutions: Macau University of Science and Technology, University of Electronic Science and Technology of China

Language: English

Topic: Quantum Information and Cryptography

Subfield: Atomic and Molecular Physics, and Optics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: green

OpenAlex ID: W7214660347

Cites: 11

Cited by:

Related to: 10