Measuring the degeneracy of discrete energy levels using a GaAs/AlGaAs quantum dot

Abstract

We demonstrate an experimental method for measuring quantum state degeneracies in bound state energy spectra. The technique is based on the general principle of detailed balance, and the ability to perform precise and efficient measurements of energy-dependent tunnelling-in and -out rates from a reservoir. The method is realized using a GaAs/AlGaAs quantum dot allowing for the detection of time-resolved single-electron tunnelling with a precision enhanced by a feedback-control. It is thoroughly tested by tuning orbital and spin-degeneracies with electric and magnetic fields. The technique also lends itself for studying the connection between the ground state degeneracy and the lifetime of the excited states.

Accepted for publication as a Letter in Physical Review Letters

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Cited by in corpus (4)

• Waiting time distribution revealing the internal spin dynamics in a double quantum dot
• Inverse counting statistics based on generalized factorial cumulants
• Direct Entropy Measurement in a Mesoscopic Quantum System
• Revealing the internal spin dynamics in a double quantum dot by periodic voltage modulation