Fig. 3: Significance of longer ranged couplings.
From: Quantifying hole-motion-induced frustration in doped antiferromagnets by Hamiltonian reconstruction

By evaluating the conditioned correlators, Eqs. (4) and (5), we estimate the strengths of longer ranged couplings up to J4. In units of the strongest interaction \({J}_{1}^{x}\), first order diagonal bonds J2 are of the order of ~10%, whereas couplings J3 reach relative magnitudes of a few percent. Due to the finite system size, J3 (J4) and higher order couplings drop to zero for nh = 0.05 (nh = 0.1), as the corresponding conditioned probabilities Eq. (5) vanish for a single (two) hole(s) per leg.