2026-03-06 東京大学
量子フィードバック制御の概念図
＜関連情報＞
- https://www.t.u-tokyo.ac.jp/press/pr2026-03-06-001
- https://journals.aps.org/prl/abstract/10.1103/48k3-tb1j
逐次量子フィードバック制御の対称性とトポロジー Symmetry and Topology of Successive Quantum Feedback Control
Junxuan Wen, Zongping Gong, and Takahiro Sagawa
Physical Review Letters Published: 5 March, 2026
DOI: https://doi.org/10.1103/48k3-tb1j
Abstract
We establish a symmetry classification for a general class of quantum feedback control. For successive feedback control with a nonadaptive sequence of bare measurements (i.e., with positive Kraus operators), we prove that the symmetry classification collapses to the ten-fold AZ† classes, specifying the allowed topology of CPTP maps associated with feedback control. We demonstrate that a chiral Maxwell’s demon with Gaussian measurement errors exhibits quantized winding numbers. Moreover, for general (nonbare) measurements, we explicitly construct a protocol that falls outside the ten-fold classification. These results broaden and clarify the principles in engineering topological aspects of quantum control robust against disorder and imperfections.
