PROJECT TITLE :

Reducing collective quantum state rotation errors with reversible dephasing

ABSTRACT:

We demonstrate that reversible dephasing via inhomogeneous broadening will greatly scale back collective quantum state rotation errors, and observe the suppression of rotation errors by more than twenty one dB in the context of collective population measurements of the spin states of an ensemble of 2.one×a hundred and five laser cooled and trapped 87Rb atoms. The large reduction in rotation noise permits direct resolution of spin state populations 13(1) dB below the elemental quantum projection noise limit. Any, the spin state measurement comes the system into an entangled state with 9.5(five) dB of directly observed spectroscopic enhancement (squeezing) relative to the standard quantum limit, whereas no enhancement would are obtained without the suppression of rotation errors.