On demand entanglement in double quantum dots via coherent carrier scattering

We show how two qubits encoded in the orbital states of two quantum dots can be entangled or disentangled in a controlled way through their interaction with a weak electron current. The transmission/reflection spectrum of each scattered electron, acting as an entanglement mediator between the dots, shows a signature of the dot–dot entangled state. Strikingly, while a few scattered carriers produce decoherence of the whole two-dot system, a larger number of electrons injected from one lead with proper energy are able to recover its quantum coherence. Our numerical simulations are based on a real-space solution of the three-particle Schrödinger equation with open boundaries. The computed transmission amplitudes are inserted in the analytical expression for the system density matrix to evaluate the entanglement.