Measuring fluorescence to track a quantum emitter's state: a theory review

  title={Measuring fluorescence to track a quantum emitter's state: a theory review},
  author={Philippe Lewalle and Sreenath K. Manikandan and Cyril Elouard and Andrew N. Jordan},
  journal={Contemporary Physics},
  pages={26 - 50}
We review the continuous monitoring of a qubit through its spontaneous emission, at an introductory level. Contemporary experiments have been able to collect the fluorescence of an artificial atom in a cavity and transmission line, and then make measurements of that emission to obtain diffusive quantum trajectories in the qubit's state. We give a straightforward theoretical overview of such scenarios, using a framework based on Kraus operators derived from a Bayesian update concept; we apply… 

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