Quantum Dynamics of Spin Qubits in Optically Active Quantum Dots

In this thesis, the dominant decoherence mechanisms of an electron spin qubit confined in an InGaAs quantum dot are identified using optical pump-probe spectroscopy. It is shown that at low magnetic fields the coherence time of the electron spin is reduced by combined effects of hyperfine and quadrupolar coupling. By employing higher-order spin correlators it is show that quantum phenomena are maintained up to microsecond timescales at magnetic fields exceeding the quadrupolar coupling strength.