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arXiv · 1204.3871

A nanomechanical resonator coupled linearly via its momentum to a quantum point contact

L. L. Benatov·M. P. Blencowe
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Abstract

We use a Born-Markov approximated master equation approach to study the symmetrized-in-frequency current noise spectrum and the oscillator steady state of a nanoelectromechanical system where a nanoscale resonator is coupled linearly via its momentum to a quantum point contact (QPC). Our current noise spectra exhibit clear signatures of the quantum correlations between the QPC current and the back-action force on the oscillator at a value of the relative tunneling phase (\eta = -\pi/2) where such correlations are expected to be maximized. We also show that the steady state of the oscillator obeys a classical Fokker-Planck equation, but can experience thermomechanical noise squeezing in the presence of a momentum-coupled detector bath and a position-coupled environmental bath. Besides, the full master equation clearly shows that half of the detector back-action is correlated with electron tunneling, indicating a departure from the model of the detector as an effective bath and suggesting that a future calculation valid at lower bias voltage, stronger tunneling and/or stronger coupling might reveal interesting quantum effects in the oscillator dynamics.

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L. L. Benatov, M. P. Blencowe. 2012-04-17. A nanomechanical resonator coupled linearly via its momentum to a quantum point contact. https://doi.org/10.1103/physrevb.86.075313

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