Geometrical phases of excitonic qubits in quantum dots

We investigate the influence of phonon mediated interactions on the non-unitary evolution of geometrical phases in excitonic qubits formed in quantum dots entangled by pure Förster coupling. We consider decoherence to occur via acoustic phonons interacting through the deformation potential and piezoelectric coupling mechanisms. The influences of bath temperature, external electric field, quantum dot size and interdot distance on the evolution of geometrical phases are examined for the GaAs/AlGaAs material system. We extend the theory to determine the effect of dynamic decoupling employing ultrafast π-pulses on the evolution of geometrical phases in the presence of dephasing processes.