Coherent control and spectroscopy of a semiconductor quantum dot Wigner molecule

TL;DR

This paper demonstrates coherent control and spectroscopy of multiple energy levels in a silicon quantum dot, revealing Wigner-molecule physics through detailed experimental and theoretical analysis.

Contribution

It reports the first coherent control of eight resonances in a strongly interacting semiconductor quantum dot, linking experimental results with Wigner-molecule theory.

Findings

Dense energy level spectrum consistent with Wigner-molecule formation

Successful spectroscopy of eight resonances in a quantum dot

Agreement between experimental data and configuration interaction calculations

Abstract

Multi-electron semiconductor quantum dots have found wide application in qubits, where they enable readout and enhance polarizability. However, coherent control in such dots has typically been restricted to only the lowest two levels, and such control in the strongly interacting regime has not been realized. Here we report quantum control of eight different resonances in a silicon-based quantum dot. We use qubit readout to perform spectroscopy, revealing a dense set of energy levels with characteristic spacing far smaller than the single-particle energy. By comparing with full configuration interaction calculations, we argue that the dense set of levels arises from Wigner-molecule physics.