LO-phonon confinement effects on the polaron properties in semiconductor quantum-well heterostructures

Polaronic corrections are calculated for a semiconductor quantum-well heterostructure at T = 0 K. Electron coupling with confined LO-phonons is assumed on the basis of an electron-LO-phonon model Hamiltonian deduced in a previous work. Screening is ignored during the calculations, a parabolic band structure is supposed and the case of completely confined electrons with infinite potential barriers at the interfaces is considered. Finite values for the electron self-energies are obtained. Dependence of polaronic corrections on the quantum-well parameters is discussed in detail and comparison with other works on the subject is made. Good agreement with experimental data is found for the case of a GaAs-Al_xGa_1−xAs quantum well.     

Superfluidity and collective oscillations of trapped Bose-Einstein condensates in a periodical potential

Quadrature squeezed cylindrically polarized modes contain entanglement not only in the polarization and spatial electric field variables but also between these two degrees of freedom [C. Gabriel et al., Phys. Rev. Lett. 106, 060502 (2011)]. In this paper we present tools to generate and detect this entanglement. Experimentally we demonstrate the generation of quadrature squeezing in cylindrically polarized modes by mode transforming a squeezed Gaussian mode. Specifically, ?1.2 dB ± 0.1 dB of amplitude squeezing are achieved in the radially and azimuthally polarized mode. Furthermore, theoretically it is shown how the entanglement contained within these modes can be measured and how strong the quantum correlations are, depending on the measurement scheme.