Eugene Polzik

Metrology and sensing at the projection noise limit and beyond

Ultimate sensitivity of metrology and sensing is defined by the fundamental principles of quantum physics. We have applied methods developed for quantum information processing [1,2] to ultra-sensitive magnetometry and atom clocks. In [3] we demonstrate the optimal sensing of an rf magnetic field with the projection noise sensitivity by suppressing the quantum noise of the meter and applying the back-action-evading measurement. Our results represent the quantum noise limited metrology with the highest-to-date number of atoms -  1012 . The sensitivity of 2*10-16 Tesla/Sqrt(Hz) for rf magnetic fields which is at the level of the current state-of-the-art in atomic magnetometry is achieved with 104 times less atoms and 5 times smaller atomic volume than the state-of-the-art. We furthermore generate atomic entanglement in the magnetometer and show that it improves the sensitivity. In [4] we demonstrate that entanglement generated on the Caesium clock transition by a quantum nondemolition measurement with 2*105 dipole trapped atoms allows us to squeeze the projection noise by 6 dB and  to improve the clock precision by 3.4 dB. The effects of dissipation on the entanglement-assisted metrology will be discussed.
 

References

  1. Quantum interface between light and atomic ensembles. K. Hammerer, A. Sørensen, and E.S. Polzik. To appear in Reviews of Modern Physics.
  2. Single mode quadrature entangled light from room temperature atomic vapour. W. Wasilewski, T. Fernholz, K. Jensen, L. S. Madsen, H. Krauter, C. Muschik, and E. S. Polzik. arXiv:0907.0132v2 [quant-ph]
  3. 3. Magnetometry at the quantum limit of sensitivity and beyond. W.Wasilewski, K. Jensen, H. Krauter, J.J. Renema, and E.S. Polzik. arXiv:0907.2453 [quant-ph].
  4. Mesoscopic atomic entanglement for precision measurements beyond the standard quantum limit. J. Appel, P. J. Windpassinger, D. Oblak, U. B. Hoff, N. Kjærgaard, and E. S. Polzik. PNAS - Proceedings of the National Academy of Science (2009) 106:10960-10965; published online before print June 17, 2009.

back to the program

print page

Zukunft aus Baden-Württemberg