Scattering approach to backaction in coherent nanoelectromechanical systems

Area of Science:

• Quantum mechanics
• Mesoscopic physics
• Condensed matter physics

Background:

• Mechanical oscillators are fundamental systems in physics.
• Measuring oscillator position with mesoscopic conductors introduces quantum backaction.
• Understanding this backaction is crucial for precision measurements.

Purpose of the Study:

• To present theoretical results for backaction force noise and damping.
• To develop a scattering approach applicable to various mesoscopic conductors.
• To investigate the influence of scattering phases on backaction.

Main Methods:

• Utilizing a scattering approach for theoretical analysis.
• Modeling a movable, gold (Au) atomic point contact.
• Employing ab initio density functional theory for calculations.

Main Results:

• The backaction is influenced by mechanical modulation of transmission probabilities.
• Backaction also depends on the modulation of scattering phases.
• This holds true even without a magnetic field.

Conclusions:

• The developed scattering approach is versatile for diverse systems.
• It extends beyond the weak tunneling limit for point contact detectors.
• Theoretical insights into quantum backaction in mesoscopic systems were provided.