Coherent electron-phonon states in suspended quantum dots: decoherence and dissipation effects

TL;DR

This paper investigates the quantum dynamics of electron-phonon states in suspended nanostructures, demonstrating coherent oscillations and external control methods, with implications for quantum device applications.

Contribution

It provides the first detailed quantum dynamical analysis of coherent electron-phonon states in suspended quantum dots, including dissipation effects and external magnetic control.

Findings

Coherent oscillations persist up to 100 mK despite thermal bath effects.

External magnetic fields can decouple electrons from phonons, controlling system dynamics.

Finite temperature reduces the lifetime of coupled states, but well-defined Rabi oscillations are observed.

Abstract

The dynamics of coherent electron-phonon (el-ph) states is investigated for a suspended nanostructure. Exact quantum dynamics calculations reveal that electron and phonons (comprising a thermal bath) couple quantum mechanically to perform coherent oscillations with periods in the range of tens of nanoseconds, despite the finite temperature of the phonon bath. Mechanical energy dissipation due to clamping loss is taken into account in the calculations. Although the lifetime of the coupled el-ph states decreases with the temperature, well defined Rabi oscillations are obtained for temperatures up to 100 mK. The dynamics of the coupled electron-phonon state is susceptible to various forms of external control. For instance, a weak external magnetic field can be used to control the dynamics of the system, by decoupling the electron from the phonon bath. The results cast light upon the underlying physics of a yet unexplored system that could be suitable for novel quantum device applications.