Spontaneous emission spectrum in double quantum dot devices

Paweł Karwat, Krzysztof Gawarecki, Katarzyna Roszak +2 more

Andreas J. Wallraff

T. Fujisawa, Tjerk H. Oosterkamp, Wilfred G. van der Wiel +4 more

A double quantum dot device is a tunable two-level system for electronic energy states. A dc electron current was used to directly measure the rates for elastic and inelastic transitions between the two levels. For inelastic transitions, energy is exchanged with bosonic degrees of freedom in the environment. The inelastic transition rates are well described by the Einstein coefficients, relating absorption with stimulated and spontaneous emission. The most effectively coupled bosons in the specific environment of the semiconductor device used here were acoustic phonons. The experiments demonstrate the importance of vacuum fluctuations in the environment for quantum dot devices and potential design constraints for their use for preparing long-lived quantum states.

Wenjing Yan, Wenfang Li, Liping Xu +2 more

Wildan Abdussalam, Paweł Machnikowski

We study the spontaneous emission from a coherently delocalized exciton state in a double quantum dot as a function of the distance between the dots, focusing on the similarities and differences between the cases of radiative (long-range, dipole) and tunnel coupling between the excitons in the dots.We show that there may be no qualitative difference between the collective emission induced by these two coupling types in spite of their essentially different physical properties.

Yinyu Liu