Fine structure of current noise spectra in nanoelectromechanical resonators

TL;DR

This paper investigates the frequency-dependent noise in a carbon nanotube quantum dot resonator, revealing how vibrational modes influence electrical noise spectra and proposing noise measurement as a tool for probing quantum vibrational damping.

Contribution

The study introduces a rigorous theoretical framework connecting vibrational properties to electrical noise spectra in nanoelectromechanical systems, highlighting the effects of electron-vibration coupling.

Findings

Resonant peaks in noise spectra at vibrational mode frequencies.

Cancellation of fine structure at symmetric tunneling barriers.

Electrical noise spectra as a sensitive probe for vibrational damping.

Abstract

We study the frequency-dependent noise of a suspended carbon nanotube quantum dot nanoelectromechanical resonator induced by electron-vibration coupling. Using a rigorous Keldysh diagrammatic technique, we establish a formal framework connecting the vibrational properties to electrical measurements. We find that the noise power spectrum exhibits a narrow resonant peak at the frequency of the vibrational modes. However, this fine structure tends to disappear due to a coherent cancellation effect when the tunneling barriers are tuned to a symmetric point. Notably, measuring the electrical current noise spectra provides a sensitive alternative method for detecting the damping and dephasing of quantum vibrational modes.