On quantum model of supergravity compensator

A new $N=1$ superfield model in $D=4$ flat superspace is suggested. This model describes dynamics of chiral compensator and can be treated as a low-energy limit of $D=4$, $N=1$ quantum superfield supergravity. Renormalization structure of this model is studied and one-loop counterterms are calculated. It is shown that the theory is infrared free. An effective action for the model under consideration is investigated in infrared domain. The lower contributions to the one-loop effective action are computed in explicit form.Comment: LaTeX, 9 page

Optical orientation of spins in GaAs:Mn/AlGaAs quantum wells via impurity-to-band excitation

The paper reports optical orientation experiments performed in the narrow GaAs/AlGaAs quantum wells doped with Mn. We experimentally demonstrate a control over the spin polarization by means of the optical orientation via the impurity-to-band excitation and observe a sign inversion of the luminescence polarization depending on the pump power. The g factor of a hole localized on the Mn acceptor in the quantum well was also found to be considerably modified from its bulk value due to the quantum confinement effect. This finding shows the importance of the local environment on magnetic properties of the dopants in semiconductor nanostructures