Quality factors of qubit rotations in single semiconductor quantum dots

摘要

The quality factors of quantum bit (qubit) rotations in single self-assembled quantum dots were investigated using photoluminescence spectroscopy. Rotations with azimuthal angle φ along the equator of the qubit sphere were implemented by varying the time delay between two π/2 pulses, resulting in a "free rotation" quality factor Q_0 = 9.8 X 10~4. Qubit rotations with polar angle θ as large as 10π along the meridian of the qubit sphere (Rabi oscillations with zero detuning) were realized with a quality factor Q_R～ 18, in experiments probing an excited excitonic state.