Emergent spinon-holon Feshbach resonance in a doped Majumdar-Ghosh model

TL;DR

This paper investigates the doped Majumdar-Ghosh model revealing emergent spinon-holon Feshbach resonance, bound states, and polarons through ARPES spectra, providing insights into dopant physics in frustrated quantum magnets.

Contribution

It introduces the observation of a tunable Feshbach resonance and bound spinon-holon states in a doped Majumdar-Ghosh model, linking few-body phenomena with frustrated magnetism.

Findings

Detection of a bound spinon-holon ground state.

Identification of a Feshbach resonance with tunable interactions.

Observation of polarons and spinon-holon molecule signatures in ARPES spectra.

Abstract

Experimental and numerical spectroscopy have revealed rich physics in antiferromagnets, in particular in frustrated and doped systems. The Majumdar-Ghosh (MG) model has an analytically known spin-disordered ground state of dimerized singlets as a result of magnetic frustration. Here we study the single-hole angle-resolved photoemission spectrum (ARPES) of a doped MG model, where we introduce a spin-hole interaction that is experimentally accessible with ultracold molecules. We report a bound spinon-holon ground state and clear signatures of a spinon-holon molecule state and polarons in the ARPES spectrum at different magnetizations. Moreover, we find signatures of an emergent Feshbach resonance with tunable interactions associated with the unbinding of the spinon and the holon. Our results provide new insights into the physics of dopants in frustrated $t$-$J$ models and establish the latter as a new platform for studies of emergent few-body phenomena.