TY - GEN
T1 - Feedback control of quantum entanglement in a two-spin system
AU - Yamamoto, Naoki
AU - Tsumura, Koji
AU - Hara, Shinji
N1 - Funding Information:
This paper was not presented at any IFAC meeting. This paper was recommended for publication in revised form by Associate Editor Rene Boel under the direction of Editor Ian Petersen. This work is supported by The Ministry of Education, Science, Sport and Culture, Japan, under Grants 06693 and 17656137.
PY - 2005
Y1 - 2005
N2 - A pair of spins is the most simple quantum system that can possess entanglement, a non-classical property playing an essential role in quantum information technologies. In this paper, feedback control problems of the two-spin system conditioned on a continuous measurement are considered. In order to make some useful formulas in stochastic control theory directly applicable, we first derive a two-dimensional description of the system. We then prove that a feedback controller stabilizes an entangled state of the two spins almost globally with probability one. Furthermore, it is shown that another entangled state, which corresponds to a non-equilibrium point of the dynamics, is stabilized via feedback in the sense that the expectation of the distance from the target can be made arbitrarily small.
AB - A pair of spins is the most simple quantum system that can possess entanglement, a non-classical property playing an essential role in quantum information technologies. In this paper, feedback control problems of the two-spin system conditioned on a continuous measurement are considered. In order to make some useful formulas in stochastic control theory directly applicable, we first derive a two-dimensional description of the system. We then prove that a feedback controller stabilizes an entangled state of the two spins almost globally with probability one. Furthermore, it is shown that another entangled state, which corresponds to a non-equilibrium point of the dynamics, is stabilized via feedback in the sense that the expectation of the distance from the target can be made arbitrarily small.
UR - http://www.scopus.com/inward/record.url?scp=33847192510&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33847192510&partnerID=8YFLogxK
U2 - 10.1109/CDC.2005.1582651
DO - 10.1109/CDC.2005.1582651
M3 - Conference contribution
AN - SCOPUS:33847192510
SN - 0780395689
SN - 9780780395688
T3 - Proceedings of the 44th IEEE Conference on Decision and Control, and the European Control Conference, CDC-ECC '05
SP - 3182
EP - 3187
BT - Proceedings of the 44th IEEE Conference on Decision and Control, and the European Control Conference, CDC-ECC '05
T2 - 44th IEEE Conference on Decision and Control, and the European Control Conference, CDC-ECC '05
Y2 - 12 December 2005 through 15 December 2005
ER -