Proposal for realizing unpaired Weyl points in a three-dimensional periodically driven optical Raman lattice

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Hauptverfasser: Lin, Xiao-Dong, Zhang, Jinyi, Zhang, Long
Format: Preprint
Veröffentlicht: 2026
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author Lin, Xiao-Dong
Zhang, Jinyi
Zhang, Long
author_facet Lin, Xiao-Dong
Zhang, Jinyi
Zhang, Long
contents In static lattice systems, the Nielsen-Ninomiya theorem enforces the pairing of Weyl points with opposite chiralities, which precludes the chiral magnetic effect (CME) in equilibrium. Periodic driving provides a viable route to circumvent this no-go constraint. Here, we propose a scheme to realize and control unpaired Weyl points using ultracold atoms in a three-dimensional (3D) optical Raman lattice under continuous periodic driving. By engineering distinct relative symmetries between the lattice and multiple Raman potentials, the configuration generates an effective 3D spin-orbit coupling and yields a tunable topological-insulator phase. Through adiabatic periodic modulation of this system, we show that eight Weyl points emerge in the quasienergy spectrum of the low-energy sector, whose net chirality can be precisely tuned. A nonzero total chirality directly corresponds to the formation of unpaired Weyl points. Furthermore, by implementing a synthetic magnetic field via laser-assisted tunneling in this setup, we demonstrate that the chirality imbalance drives a quantized charge current in the weak-field regime, providing a direct signature of the CME. We verify that the adiabatic condition of the driving protocol, as well as the proposed experimental preparation and detection techniques, are within reach of current ultracold-atom experiments. This work establishes a realistic and controllable platform for exploring chiral-anomaly physics and nonequilibrium topological phenomena linked to Weyl fermions.
format Preprint
id arxiv_https___arxiv_org_abs_2602_11935
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Proposal for realizing unpaired Weyl points in a three-dimensional periodically driven optical Raman lattice
Lin, Xiao-Dong
Zhang, Jinyi
Zhang, Long
Quantum Gases
Mesoscale and Nanoscale Physics
High Energy Physics - Lattice
In static lattice systems, the Nielsen-Ninomiya theorem enforces the pairing of Weyl points with opposite chiralities, which precludes the chiral magnetic effect (CME) in equilibrium. Periodic driving provides a viable route to circumvent this no-go constraint. Here, we propose a scheme to realize and control unpaired Weyl points using ultracold atoms in a three-dimensional (3D) optical Raman lattice under continuous periodic driving. By engineering distinct relative symmetries between the lattice and multiple Raman potentials, the configuration generates an effective 3D spin-orbit coupling and yields a tunable topological-insulator phase. Through adiabatic periodic modulation of this system, we show that eight Weyl points emerge in the quasienergy spectrum of the low-energy sector, whose net chirality can be precisely tuned. A nonzero total chirality directly corresponds to the formation of unpaired Weyl points. Furthermore, by implementing a synthetic magnetic field via laser-assisted tunneling in this setup, we demonstrate that the chirality imbalance drives a quantized charge current in the weak-field regime, providing a direct signature of the CME. We verify that the adiabatic condition of the driving protocol, as well as the proposed experimental preparation and detection techniques, are within reach of current ultracold-atom experiments. This work establishes a realistic and controllable platform for exploring chiral-anomaly physics and nonequilibrium topological phenomena linked to Weyl fermions.
title Proposal for realizing unpaired Weyl points in a three-dimensional periodically driven optical Raman lattice
topic Quantum Gases
Mesoscale and Nanoscale Physics
High Energy Physics - Lattice
url https://arxiv.org/abs/2602.11935