It is a widely accepted view that the interplay of spin and charge degrees of freedom in doped antiferromagnets (AFMs) yields the rich physics of high-temperature superconductors. Nevertheless, it remains unclear how effectively low-energy degrees of freedom and corresponding field theories emerge from microscopic models such as tJ and the Hubbard Hamiltonian. A promising view is that charge carriers have an abundant internal parton structure at intermediate scales, but the interaction of emergent partons with collective magnon excitations in ambient AFM remains unexplored. Here we study a one-dimensional spin chain doped with a staggered magnetic field and show that it supports a zoo of different long-lived excitations. These include magnons. Mesonic pairs of spinons and chargons and their rotational vibrational excitations. Tetrapalton bound states of mesons and magnons. We use DMRG simulations to identify these types of quasiparticles in different spectra. In addition, we present a strong-coupling theory that describes the molecular coupling of mesons to polaronic dressing and collective magnon excitations. Effective theories can be solved by standard tools developed for polaronic problems and can be extended in the future to study similar physics in two-dimensional doped AFM. Experimentally, quantum gas microscopy can directly realize doped spin chains in staggered fields.
