Ground state critical exponents in disordered XYZ spin chain

We perform a study of the XYZ spin chain model with random independently distributed couplings. We focus on the critical line between x and y Ising antiferromagnetic phases, given by identical x and y distributions with a z-coupling distribution of varying bandwidth. In this way one can tune between the free-fermion fixed point and the multicritical point with identically distributed couplings in all directions. Using a new unbiased numerically exact method called rigorous renormalization group (RRG) we target the ground state physics, focusing on evaluating critical exponents, which have been proposed to vary continuously along the critical line between the XY and statistically isotropic XYZ points based on quantities computed using strong disorder RG schemes. Similarly, we investigate the critical line between the U(1) symmetric XX point and the anisotropic XY point.