Linewidth Broadening of Coupled Quantum Dot Pairs*

Solid state atoms are promising systems for emerging quantum technologies. The harnessing of coherences in these systems offers a route to quantum-enhanced devices for sensing, information processing and communications. Crucial for the realization of such technology is the understanding of the dephasing, relaxation and fluctuation processes affecting quantum states in the solid state environment in order to mitigate, eliminate and utilize these processes. In the optical spectra these phenomena are prominent via the linewidth broadening and line profile of optical transitions. We perform a detailed analysis of linewidth broadening of spatially direct, indirect excitons and examine the linewidth as function of electric field including the tunneling resonances. The study yields new insights on the broadening mechanisms for different charge and spin configurations in coupled quantum dots systems as a function of temperature and tunnel coupling strength.