Real-time deterministic generation of maximally entangled two-qubit and three-qubit states via bang-bang control

摘要

We exploit the notion of SWM-(simultaneous-weak-measurements)-induced quantum state reduction, enablingnthe use of measurement backaction to produce the desired quantum states. The probabilistic generation ofnmaximally entangled Bell states and the |GHZu0002 (Greenberger-Horne-Zeilinger) state are then performed as anconsequence of this notion. By combining SWM-induced quantum state reduction with feedback control, we arenable to deterministically generate any desired Bell state as well as the |GHZu0002 state, without the knowledge ofnthe initial state. The control-computation time is compensated for by the delay time in the time-delay bang-bangncontrol, through which the real-time implementation of the control scheme is guaranteed. The effectiveness ofnthe proposed scheme is illustrated numerically.