Real-time dynamics and optical excitations of capacitively coupled quantum many-body heterostructures

We compute and analyze the optical excitations and real-time dynamics, induced by the light-matter interaction, of capacitively coupled heterostructures, composed of one-dimensional quantum many-body subsystems modeled by a Hubbard-like Hamiltonian. Our numerical study was carried out using time-dependent matrix product states. The optical excitations of the isolated subsystems are greatly modified due to the capacitive coupling between them. Remarkably, we find negative values for the optical conductivity of one of the subsystems for intermediate values of the capacitive coupling, evidencing a perfect negative drag effect due to the quantum entanglement of two perfectly interlocked charge density waves. At weak coupling, we detect optical excitations which are perturbatively connected to those of the isolated subsystems. Additionally, we find that the heterostructure tends to store capacitive energy at the expense of a reduction of the electron mobility. This effect has been observed experimentally in vertically-grown quantum wires.