New topology of electron-photon states in cavity quantum materials

Topological materials exhibit extraordinary properties, thanks to the unique characteristics of their electronic wavefunctions. To grasp this concept, think of it as counting the holes in everyday objects—a donut, regardless of its size or toppings, unequivocally boasts one hole. Similarly, non-zero integer values known as “Chern numbers” serve as signatures of intricate topological phases in materials.

In their study, the researchers of the THEORIE team delve into a remarkable phenomenon. By immersing a 2D material within a cavity resonator, they’ve unveiled a fascinating capability to reshape its inherent topology. This transformation arises from a captivating interplay between an electron and a cavity quantum electromagnetic field, akin to an intricate dance where partners become profoundly entangled.

Traditionally, the electron Chern number was deemed a paramount topological property. However, within the entwined realm of electron-photon interactions, the electron Chern number loses its exclusive status. Instead, the researchers made a fascinating discovery—an entirely new Chern number emerges, one intricately linked to the hybrid electron-photon eigenstates. This revelation reshapes our understanding of material topology and opens doors to unprecedented possibilities in the realm of quantum materials.

Reference :

Electron-photon Chern number in cavity-embedded 2D moiré materials

Danh-Phuong Nguyen, Geva Arwas, Zuzhang Lin, Wang Yao, and Cristiano Ciuti

Phys. Rev. Lett. 131, 176602 (2023)