The competition between the Coulomb interaction and the binding forces due to the confinement and the magnetic field induces transitions of the ground state of quantum dots with few electrons. We demonstrate that for quantum dot helium these transitions occur between states with differently strong correlations between the electrons. By the response of quantum dot helium to far infrared radiation we exemplify that a proper treatment of the correlation effects may be essential for a correct interpretation of experimental data on quantum dots with few electrons.
Bibliographical noteFunding Information:
We acknowledge stimulating discussions with B. Meurer and D. Heitmann. Calculations resulting in fig. 3 were performed by K. Neurohr. This research was supported in part by the Icelandic Natural Science Foundation, the Bun-desminister f/Jr Forschung und Technologie under contract number TK0375/2 and the UK Science and Engineering Research Council.