Entangled Terahertz Photon Emission from Topological Insulator Quantum Dots

TL;DR

This paper proposes a feasible method to generate entangled terahertz photon pairs using topological insulator quantum dots, leveraging their unique properties to overcome common entanglement challenges.

Contribution

It introduces a novel scheme utilizing topological insulator quantum dots that inherently lack fine structure splitting, enabling robust entangled photon emission.

Findings

Fine structure splitting is absent in TIQDs due to time-reversal symmetry.

Selection rules are governed by winding number conservation.

Entanglement remains robust despite disorders and shape irregularities.

Abstract

We propose an experimentally feasible scheme for generating entangled terahertz photon pairs in topological insulator quantum dots (TIQDs). We demonstrate theoretically that in generic TIQDs: 1) the fine structure splitting, which is the obstacle to produce entangled photons in conventional semiconductor quantum dots, is inherently absent for one-dimensional massless excitons due to the time-reversal symmetry; 2) the selection rules obey winding number conservation instead of the conventional angular momentum conservation between edge states with a linear dispersion. With these two advantages, the entanglement of the emitted photons during the cascade in our scheme is robust against unavoidable disorders and irregular shapes of the TIQDs.