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Entangled Terahertz Photon Emission from Topological Insulator Quantum Dots

Research paper by Li-kun Shi, Kai Chang, Chang-Pu Sun

Indexed on: 31 Jan '16Published on: 31 Jan '16Published in: Physics - Mesoscopic Systems and Quantum Hall Effect



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.