Observation of low-lying excitations of electrons in coupled quantum dots

TL;DR

This study investigates low-lying electron excitations in coupled quantum dots using resonant inelastic light scattering, revealing intra- and intershell excitations influenced by confinement and tunneling, with implications for quantum entanglement research.

Contribution

It provides experimental observation of electron excitations in coupled quantum dots and links these to the interplay of confinement energy and tunneling gap, advancing understanding of artificial molecular states.

Findings

Identification of intra- and intershell excitations

Energy dependence on confinement and tunneling parameters

Narrow linewidths suggest suitability for entanglement studies

Abstract

Tunneling excitations of electrons in dry-etched modulation-doped AlGaAs/GaAs coupled quantum dots (QDs) are probed by resonant inelastic light scattering. A sequence of intra- and intershell excitations are found at energies determined by the interplay between the QD confinement energy $\hbar \omega_0$ and the tunneling gap $\Delta_{SAS}$, the splitting between the symmetric and anti-symmetric delocalized single particle molecular states. The narrow line-widths displayed by electronic excitations in these nanostructures indicate promising venues for the spectroscopic investigation of entanglement of electron states in these artificial molecules.