Many-body localization to spin glass phase transition in disordered spin-chain system

Disorder in a strongly correlated spin-chain system can give rise to novel phases of matter, such as many-body localization (MBL) phases or spin-glass (SG) phases. The two phases share similar non-thermalizing properties due to the existence of extensive set of local integrals of motion (LIOMs), and the SG phases feature in other properties such as a SG order parameter as well as the doubly degenerate eigenstates.

We consider a disordered Heisenberg XXZ model with on-site random field and random anisotropy. By changing the relative strength between these two disorders, we numerically observe the phase transition from MBL to SG, using numerically constructed LIOMs. We also obtain a scaling property of this transition, which elucides the phase diagram of this system in the thermaldynamic limit.