Far-infrared response of quantum-dot molecules

We report an analysis of the dipole response of a symmetric quantum-dot mol ecule as a function of the dot-dot separation and intensity of a perpendicu lar magnetic field. The potential barrier is assumed proportional to the in terdot distance using a two-center oscillator potential. The results are ob tained within the symmetry-unrestricted TDLSDA. It is shown that the FIR de tails, specially the fragmentation of the low-energy brach, are quite, sens itive to the interdot separation and that in both the small and large separ ation limits the results converge towards the analytic Kohn's magnotoplasmo n energies. The validity of the LSDA is checked by comparison with the Hart ree-Fock dipole spectrum in one case.