@article {618,
	title = {Causal structure of interacting Weyl fermions in condensed matter systems},
	journal = {Nat. Commun.},
	volume = {14},
	year = {2023},
	pages = {2228},
	abstract = {The spacetime light cone is central to the definition of causality in the theory of relativity. Recently, links between relativistic and condensed matter physics have been uncovered, where relativistic particles can emerge as quasiparticles in the energy-momentum space of matter. Here, we unveil an energy-momentum analogue of the spacetime light cone by mapping time to energy, space to momentum, and the light cone to the Weyl cone. We show that two Weyl quasiparticles can only interact to open a global energy gap if they lie in each other{\textquoteright}s energy-momentum dispersion cones{\textendash}analogous to two events that can only have a causal connection if they lie in each other{\textquoteright}s light cones. Moreover, we demonstrate that the causality of surface chiral modes in quantum matter is entangled with the causality of bulk Weyl fermions. Furthermore, we identify a unique quantum horizon region and an associated {\textquoteright}thick horizon{\textquoteright} in the emergent causal structure.},
	doi = {10.1038/s41467-023-37931-w},
	url = {https://www.nature.com/articles/s41467-023-37931-w},
	author = {Wei-Chi Chiu and Guoqing Chang and Gennevieve Macam and Ilya Belopolski and Shin-Ming Huang and Robert Markiewicz and Jia-Xin Yin and Zi-Jia Cheng and Chi-Cheng Lee and Tay-Rong Chang and Feng-Chuan Chuang and Su-Yang Xu and Hsin Lin and M. Zahid Hasan and Arun Bansil}
}
