Quantum-correlated photons generated by nonlocal electron transport
Authors: Hellbach F., Pauly F., Belzig W., Rastelli G.
Autors Affiliation: Fachbereich Physik, Universitdt Konstanz, 78457 Konstanz, Germany; Institute of Physics, University of Augsburg, 86135 Augsburg, Germany; INO-CNR BEC Center and Dipartimento di Fisica, Universita di Trento, 38123 Povo, Italy
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 using a diagrammatic perturbative expansion based on Keldysh Green´s functions to fourth order in the dot-cavity interaction strength, taking into account vertex diagrams. Furthermore, 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 detuning or a single dot coupled to two cavities, we show that the inequality is not violated.
Journal/Review: PHYSICAL REVIEW B
Volume: 105 (24) Pages from: L241407-1 to: L241407-7
More Information: This work was supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) through Project No. 32152442 -SFB 767 and Project No. 25217212 -SFB 1432 and by the German Excellence Strategy via the Zukunftskolleg of the University of Konstanz.KeyWords: quantum transport, quantum dots, quantum microwave resonators, entanglementDOI: 10.1103/PhysRevB.105.L241407