Entangled Photon Pair Generation in Hybrid Superconductor-Semiconductor Quantum Dot Devices

TL;DR

This paper explores how coupling low-symmetry quantum dots to superconductors can modify energy levels and enhance photon entanglement, advancing quantum dot-based entangled photon sources.

Contribution

It introduces a method to manipulate biexciton and exciton energy levels in quantum dots via superconducting coupling, enabling improved entanglement in photon emission.

Findings

Superconducting coupling shifts biexciton energy levels.

Spectroscopic separation of exciton and biexciton can be reduced.

Photon entanglement concurrence can be enhanced.

Abstract

We investigate the effect of Cooper pair injection in shifting biexciton energy level of low-symmetry (C2v) quantum dots (QDs) exhibiting nontrivial fine structure splitting. Coupling QDs to the superconducting coherent state forms extra fine structures by intermixing the ground and biexcitonic states where spectroscopic separation of neutral exciton and biexciton can be diminished, yielding a system to be utilized in time reordering scheme. The separability of exciton and biexciton energy levels is ascribed to the corresponding direct, exchange and correlation energies calculated here through configuration interaction method. We demonstrate the possibility of enhancing photon entanglement concurrence via providing an energy coincidence for biexciton-exciton (XX \rightarrow X) and exciton-ground (X \rightarrow 0) emissions within the weak coupling regime.