Electron Spin

Jan C. A. Boeyens

Explanation and clarification of electron spin.

Arno Böhm

Özgür Çakır, T. Takagahara

Hyperfine interaction of electron spins with nuclear spins, in coupled double quantum dots is studied. Results of successive electron spin measurements exhibit bunching due to correlations induced via the nuclear spins. Further nuclear spins can be purified via conditional electron spin measurements which lead to electron spin revivals in the conditional probabilities. The electron spin coherence time can be extended via conditional measurements. The results are extended to a single electron on a single QD.

Shingo Kukita, Hideaki Ookane, Yuichiro Matsuzaki +1 more

Electron-spin resonance is a useful tool to investigate properties of materials in magnetic fields where high spin polarization of target electron spins is required in order to obtain high sensitivity. However, the smaller the magnetic fields becomes, the more difficult it is to obtain high polarization by thermalization. Here, we propose to employ a superconducting flux qubit (FQ) to polarize electron spins actively. We have to overcome a large energy difference between the FQ and electron spins for efficient energy transfer among them. For this purpose, we adopt a spin-lock technique on the FQ where the Rabi frequency associated with the spin-locking can match the resonance (Larmor) one of the electron spins. We find that adding dephasing on the spins is beneficial to obtain high polarization of them, because otherwise the electron spins are trapped in dark states that cannot be coupled with the FQ. We show that our scheme can achieve high polarization of electron spins in realistic experimental conditions.

Arno Böhm, Mark E. Loewe