Doublon life times in dissipative environments

We study the dissipative decay of states with a doubly occupied site in a two-electron Hubbard model, known as doublons. For the environment we consider charge and current noise which are modelled as a bosonic heat bath that couples to the onsite energies and the tunnel couplings, respectively. It turns out that the dissipative decay depends qualitatively on the type of environment as for charge noise, the life time grows with the electron-electron interaction. For current noise, by contrast, doublons become increasingly unstable with larger interaction. Numerical studies within a Bloch-Redfield approach are complemented by analytical estimates for the decay rates. For typical quantum dot parameters, we predict that the doublon life times up to 50 ns.