# Parton theory of magnetic polarons: Mesonic resonances and signatures in dynamics. (arXiv:1712.01874v1 [cond-mat.quant-gas])

When a mobile hole is moving in an anti-ferromagnet it distorts the

surrounding Neel order and forms a magnetic polaron. Such interplay between

hole motion and anti-ferromagnetism is believed to be at the heart of high-Tc

superconductivity in cuprates. We study a single hole described by the t-Jz

model with Ising interactions between the spins in 2D. This situation can be

experimentally realized in quantum gas microscopes. When the hole hopping is

much larger than couplings between the spins, we find strong evidence that

magnetic polarons can be understood as bound states of two partons, a spinon

and a holon carrying spin and charge quantum numbers respectively. We introduce

a microscopic parton description which is benchmarked by comparison with

results from advanced numerical simulations. Using this parton theory, we

predict a series of excited states that are invisible in the spectral function

and correspond to rotational excitations of the spinon-holon pair. This is

reminiscent of mesonic resonances observed in high-energy physics, which can be

understood as rotating quark antiquark pairs. We also apply the strong coupling

parton theory to study far-from equilibrium dynamics of magnetic polarons

observable in current experiments with ultracold atoms. Our work supports

earlier ideas that partons in a confining phase of matter represent a useful

paradigm in condensed-matter physics and in the context of high-Tc

superconductivity. While direct observations of spinons and holons in real

space are impossible in traditional solid-state experiments, quantum gas

microscopes provide a new experimental toolbox. We show that, using this

platform, direct observations of partons in and out-of equilibrium are

possible. Extensions of our approach to the t-J model are also discussed. Our

predictions in this case are relevant to current experiments with quantum gas

microscopes for ultracold atoms.