Tunable and Robust Long-Range Coherent Interactions between Quantum Emitters Mediated by Weyl Bound States

Article: Published in Physical Review Letters by Jorge Bravo-Abad member of the Theoretical Condensed Matter Physics Department and IFIMAC researcher.

Obtaining long-distance coherent interactions is one of the current frontiers in atomic physics. Such interactions can be harnessed, for example, to induce long-distance entanglement between emitters, create large optical nonlinearities, or study long-range interacting many-body physics in the context of quantum simulation, where they are known to lead to qualitatively different physics than short-ranged interactions. However, these interactions are unavoidably accompanied by significant individual and collective dissipation.

In this recent Physical Review Letters paper, IFIMAC researcher Jorge Bravo-Abad, in collaboration with Iñaki García-Elcano (PhD student of the Theoretical Condensed Matter Physics Department) and Prof. Alejandro Gonzalez-Tudela (Instituto de Física Fundamental, CSIC), showed that photonic Weyl environments can enable for the first time coherent interactions between quantum emitters featuring negliglible dissipation, power-law scaling, tunability, and robustness to disorder.

The authors of this work found that when the frequency of the emitters matches that of a photonic Weyl point, an exotic light-matter bound state, able to mediate coherent power-law interactions between the quantum emitters with virtually no dissipation, emerges in the system. Furthermore, they showed how those interactions inherit two important features from the topological protection of Weyl points: First, the photonic band structure around the Weyl points can be modified without opening a band gap; this enables tuning the power-law exponent of the interaction. Second, this power-law behavior is robust to disorder in the system’s bath.

The combination of all these features in the same platform (i.e., a single platform enabling coherent, power-law, no dissipative, tunable, and robust to disorder interactions between QEs) has never been predicted or reported in any other photonic environment, and could ultimately pave the way for the design of more robust long-distance entanglement protocols or quantum simulation implementations for studying long-range interacting systems. [Full article]

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