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Published on: November 11, 2013
Stroboscopic backaction evasion in a dense alkali-metal vapor
G Vasilakis1, V Shah, M V Romalis
1Department of Physics, Princeton University, Princeton, New Jersey 08544, USA.
Abstract:
We explore experimentally quantum nondemolition measurements of atomic spin in a hot potassium vapor in the presence of spin-exchange relaxation. We demonstrate a new technique for backaction evasion by stroboscopic modulation of the probe light. With this technique we study spin noise as a function of polarization for atoms with spin greater than 1/2 and obtain good agreement with a simple theoretical model. We point that, in a system with fast spin exchange, where the spin-relaxation rate is changing with time, it is possible to improve the long-term sensitivity of atomic magnetometry by using quantum nondemolition measurements.
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