Quantum backaction in spinor-condensate magnetometry
We provide a theoretical treatment of the quantum backaction of Larmor frequency measurements on a spinor Bose-Einstein condensate by an off-resonant light field. Two main results are presented; the first is a "quantum jump" operator description that reflects the abrupt change in the spin state of the atoms when a single photon is counted at a photodiode. The second is the derivation of a conditional stochastic master equation relating the evolution of the condensate density matrix to the measurement record. We provide a few examples of the application of this formalism and comment on its application to metrology.
Additional Information© 2013 American Physical Society. Received 12 November 2012; revised manuscript received 26 August 2013; published 3 December 2013. This work was supported by the Defense Advanced Research Project Agency (DARPA) QuASAR program through a grant from AFOSR, by the DARPA ORCHID program through a grant from the US Army Research Office, and by NSF. M.V. acknowledges support from the Alfred P. Sloan Foundation. The authors would also like to thank Carlo Samson and Chandra Raman of the Georgia Institute of Technology for useful input on additional experimental considerations.
Published - PhysRevA.88.063809.pdf
Submitted - 1211.2870v1.pdf