English

Optimality of feedback control strategies for qubit purification

Quantum Physics 2008-07-09 v2

Abstract

Recently two papers [K. Jacobs, Phys. Rev. A {\bf 67}, 030301(R) (2003); H. M. Wiseman and J. F. Ralph, New J. Physics {\bf 8}, 90 (2006)] have derived control strategies for rapid purification of qubits, optimized with respect to various goals. In the former paper the proof of optimality was not mathematically rigorous, while the latter gave only heuristic arguments for optimality. In this paper we provide rigorous proofs of optimality in all cases, by applying simple concepts from optimal control theory, including Bellman equations and verification theorems.

Keywords

Cite

@article{arxiv.0707.3001,
  title  = {Optimality of feedback control strategies for qubit purification},
  author = {Howard M. Wiseman and Luc Bouten},
  journal= {arXiv preprint arXiv:0707.3001},
  year   = {2008}
}

Comments

6 pages. very minor improvements

R2 v1 2026-06-21T09:00:00.400Z