Experimental recovery of a partially-collapsed qubit
Abstract
We implemented and tested a process for recovering quantum information following a weak measurement whereby a qubit may spontaneously decay outside the computational basis. Alike in spirit and form to a classical spin echo, the recovery protocol and expected fidelity is, in principle, perfect and independent of the initial qubit state. To demonstrate the partial decay and recovery process, we engineered a novel qubit from the Zeeman spin-states of a single trapped 40Ca+ ion's excited 3D5/2 electronic state. Tuning the strength of a near-resonant laser pulse allows us to realize a variable qubit decay rate. Even with a spontaneous decay probability of 0.8, we demonstrated recovery of the qubit's state vector with a fidelity of F = 0 . 986 , a better result than is achievable merely by post-selection of results from un-decayed qubits.
- Publication:
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APS Division of Atomic, Molecular and Optical Physics Meeting Abstracts
- Pub Date:
- May 2014
- Bibcode:
- 2014APS..DMP.P4006S