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Just as Quantum dots can display the energy transitions characteristics of electron in a conventional hydrogenic atom to give emission tunability, can it and other similar electron confinement system has hyperfine transitions?

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  • $\begingroup$ In what wavelength magitude is the emissions of electrons transitions under in the Zeeman/Stark effects? $\endgroup$ Commented Aug 7, 2021 at 4:47
  • $\begingroup$ @NelsonVanegasA. That is completely wrong, there are actually many nuclei which interact with the election via hyperfine interactions in a quantum dot (many, many thousands). They are individually smaller than in the atomic case, but they are important for quantum dot decoherence $\endgroup$
    – KF Gauss
    Commented Jun 10, 2023 at 16:27

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TLDR, Hyperfine interactions are very important for quantum dot qubits, although they are usually a nuisance because they interact with your electronic spin state incoherently.

Unlike atoms in vacuum, electrons in quantum dots interact via hyperfine interactions with all the nuclei in the dot (i.e., tens to hundreds of thousands of nuclei). This interaction is generally incoherent and noisy because the overlap with any individual nucleus is tiny, there are many thousands of them, and the nuclei are generally in a thermal spin state unless there is a large magnetic field.

It is unusual to see well defined hyperfine splitting in quantum dots unless you purposely engineer the system (e.g., using small dot dimensions, high isotope purity, donor qubits etc.).

Rather than hyperfine splittings, it is typical to see hyperfine interactions causing your qubit levels to broaden in linewidth on the seconds time scale.

For example, you can reference this paper which describes how the hyperfine interaction is a leading mechanism for the decay of a spin qubit in a quantum dot.

Here is another example which measured the hyperfine interaction by spin polarizing the nuclei with optical light. Note that they do not see the hyperfine level splitting directly like you do in atomic physics.

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