Squeezing of a nanomechanical resonator by quantum nondemolition measurement and feedback
We analyze squeezing of the nanoresonator state produced by periodic measurement of position by a quantum point contact or a single-electron transistor. The mechanism of squeezing is the stroboscopic quantum nondemolition measurement generalized to the case of continuous measurement by a weakly coupled detector. The magnitude of squeezing is calculated for the harmonic and stroboscopic modulations of measurement, taking into account detector efficiency and nanoresonator quality factor. We also analyze the operation of the quantum feedback, which prevents fluctuations of the wave packet center due to measurement back-action. Verification of the squeezed state can be performed in almost the same way as its preparation; a similar procedure can also be used for the force detection with sensitivity beyond the standard quantum limit.
Additional Information© 2005 American Physical Society. Received 22 November 2004; revised manuscript received 31 January 2005; published 9 June 2005. The authors would like to thank D. Averin, A. Doherty, S. Habib, K. Jacobs, K. Likharev, I. Martin, A. Matsko, and G. Milburn for fruitful discussions and remarks. The work was supported by NSA and ARDA under ARO Grants Nos. DAAD19-01-1-0491 and W911NF-04-1-0204 (R.R. and A.N.K.) and by NSA (K.S.).
Published - PhysRevB.71.235407.pdf
Submitted - 0411617v1.pdf