Magnetic control of exciton interaction in double quantum wells

We discuss dipole exciton behavior against strong magnetic field in double quantum wells. It is found that the system shows a transition of dipole exciton configuration, from anisotropic to isotropic configuration, with increasing applied magnetic field. This changes the nature of exciton interactions, yielding controllability of nature of the exciton interaction by magnetic field. This should be crucial for stable condensation of exciton. The excitation characteristic of the anisotropic configuration, whose dispersion relation is E∼k, is also discussed.