Inspired by investigations of Dirac, Majorana, and Weyl fermions in the context of particle, condensed-matter, and atomic physics, we propose theoretical and experimental platforms to create and detect massless helical boson modes that we call Weyl bosons, the bosonic cousin of Weyl fermions. We show that these exotic excitations arise in one-dimensional interacting Fermi gases, when spin-orbit coupling and Rabi fields are present. We obtain the phase diagram of chemical potential versus Rabi fields for given spin-orbit coupling and interactions, showing regions where zero, one, or two types of Weyl bosons exist. We find that, when two types of Weyl bosons emerge, they must propagate with different velocities. Furthermore, we show that the disappearance of any Weyl boson species is described by a topological quantum phase transition of the Lifshitz type, where the velocity of the disappearing Weyl boson vanishes and the velocity of the surviving Weyl boson develops a cusp at the transition boundary. Lastly, to detect the existence of Weyl bosons, we propose measurements of the dynamical structure factor tensor (charge-charge, charge-spin, and spin-spin), where the energy dispersions, spectral weights, and helicities of the emergent Weyl bosons can be experimentally extracted in systems such as ${}^6\mathrm{Li}, {}^{40}\mathrm{K}$, and ${}^{173}\mathrm{Yb}$.

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• Cold atoms & matter waves
• Quasiparticles & collective excitations
• Spin-orbit coupling
• Fermi gases