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Title: Quantum-limited velocity readout and quantum feedback cooling of a trapped ion via electromagnetically induced transparency

Journal Article · · Physical Review. A
; ;  [1]
  1. Institute for Theoretical Physics, University of Innsbruck, and Institute for Quantum Optics and Quantum Information of the Austrian Academy of Science, 6020 Innsbruck (Austria)

We discuss continuous observation of the momentum of a single atom by employing the high velocity sensitivity of the index of refraction in a driven {lambda}-system based on electromagnetically induced transparency. In the ideal limit of unit collection efficiency this provides a quantum-limited measurement with minimal backaction on the atomic motion. A feedback loop, which drives the atom with a force proportional to measured signal, provides a cooling mechanism for the atomic motion. We derive the master equation which describes the feedback cooling and show that in the Lamb-Dicke limit the steady state energies are close to the ground state, limited only by the photon collection efficiency. Outside of the Lamb-Dicke regime the predicted temperatures are well below the Doppler limit.

OSTI ID:
20718815
Journal Information:
Physical Review. A, Vol. 72, Issue 4; Other Information: DOI: 10.1103/PhysRevA.72.043823; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1050-2947
Country of Publication:
United States
Language:
English