Zeno and Anti-Zeno Polarization Control of Spin Ensembles by Induced Dephasing | Phys. Rev. Lett. 105, 160401 (2010)
Zeno and Anti-Zeno Polarization Control of Spin Ensembles by Induced Dephasing
Gonzalo A. Álvarez1,2, D. D. Bhaktavatsala Rao3, Lucio Frydman3,*, and Gershon Kurizki3,†
1Facultad de Matemática, Astronomía y Física, Universidad Nacional de Córdoba, 5000 Córdoba, Argentina
2Fakultät Physik, Universität Dortmund, Otto-Hahn-Strasse 4, D-44221 Dortmund, Germany
3Department of Chemical Physics, Weizmann Institute of Science, Rehovot, 76100, Israel
Received 26 May 2010; revised 19 July 2010; published 12 October 2010
We experimentally and theoretically demonstrate the purity (polarization) control of qubits entangled with multiple spins, using induced dephasing in nuclear magnetic resonance setups to simulate repeated quantum measurements. We show that one may steer the qubit ensemble towards a quasiequilibrium state of a certain purity by choosing suitable time intervals between dephasing operations. These results demonstrate that repeated dephasing at intervals associated with the anti-Zeno regime leads to ensemble purification, whereas those associated with the Zeno regime lead to ensemble mixing.
© 2010 The American Physical Society
