Quantum Computing, Communication, and Simulation
Quantum sensing and ghost imaging
L. Davidovich, R. L. de Matos Filho
Abstract
We show that the strategy of ghost imaging can be successfully adapted to the estimation of parameters of open systems. Two entangled qubits, so that only one of them interacts with a depolarizing sample, may lead to precision in the estimation of the depolarizing parameter better than the one corresponding to sending the pair, entangled or not, through the sample. As opposed to ghost imaging, entanglement plays an essential role in this case, as does the entangling detection procedure, consisting in projecting the final state on a Bell-state basis. For isotropic depolarization, quantum advantage is obtained only when the final state, after interaction with the sample, is not entangled anymore.