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arXiv · 2110.12814

Quantum-correlated photons generated by nonlocal electron transport

Felicitas Hellbach·Fabian Pauly·Wolfgang Belzig·Gianluca Rastelli
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Abstract

Since the realization of high-quality microwave cavities coupled to quantum dots, one can envisage the possibility to investigate the coherent interaction of light and matter in semiconductor quantum devices. Here we study a parallel double quantum dot device operating as single-electron splitter interferometer, with each dot coupled to a local photon cavity. We explore how quantum correlation and entanglement between the two separated cavities are generated by the coherent transport of a single electron passing simultaneously through the two different dots. We calculate the covariance of the cavity occupations by use of a diagrammatic perturbative expansion based on Keldysh Green's functions to the fourth order in the dot-cavity interaction strength, taking into account vertex diagrams. In this way, we demonstrate the creation of entanglement by showing that the classical Cauchy-Schwarz inequality is violated if the energy levels of the two dots are almost degenerate. For large level detunings or a single dot coupled to two cavities, we show that the inequality is not violated.

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Felicitas Hellbach, Fabian Pauly, Wolfgang Belzig, Gianluca Rastelli. 2021-10-25. Quantum-correlated photons generated by nonlocal electron transport. https://doi.org/10.1103/physrevb.105.l241407

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