17 research outputs found
Polarization-Correlated Photon Pairs from a Single Quantum Dot
Polarization correlation in a linear basis, but not entanglement, is observed
between the biexciton and single-exciton photons emitted by a single InAs
quantum dot in a two-photon cascade. The results are well described
quantitatively by a probabilistic model that includes two decay paths for a
biexciton through a non-degenerate pair of one-exciton states, with the
polarization of the emitted photons depending on the decay path. The results
show that spin non-degeneracy due to quantum-dot asymmetry is a significant
obstacle to the realization of an entangled-photon generation device.Comment: 4 pages, 4 figures, revised discussio
Symmetry of anisotropic exchange interactions in semiconductor nanostructures
The symmetry of exchange interaction of charge carriers in semiconductor
nanostructures (quantum wells and quantum dots) is analysed. It is shown that
the exchange Hamiltonian of two particles belonging to the same energy band can
be universally expressed via pseudospin operators of the particles. The
relative strength of the anisotropic exchange interaction is shown to be
independent of the binding energy and the isotropic exchange constant