Speaker
Description
Recent quantum simulation experiments by Google Quantum AI have realized disorder-free localization in lattice gauge theories without explicitly sampling disorder realizations. In such schemes, however, the effective disorder is generated by finite-dimensional gauge or ancilla degrees of freedom, raising a basic question: when does a truncated gauge field faithfully reproduce the physics of many-body localization (MBL)? We address this question in a Z2 lattice gauge theory dual to a mixed-field Ising chain with n-level bond disorder, directly motivated by recent quantum simulation experiments. Combining exact diagonalization and infinite matrix product state techniques, we show that binary disorder (n = 2) does not support a robust localized regime on accessible system sizes and times. Instead, its nonergodic signatures are better understood as slow prethermal dynamics arising from energy-scale separation and approximate Hilbert-space fragmentation. By contrast, already n = 4 yields strong MBL-like behavior, including Poissonian level statistics, area-law eigenstate entanglement, strongly nonthermal entanglement spectra, and persistent memory of local observables in the thermodynamic limit. Our results identify gauge-field truncation as a relevant physical control parameter—not merely a numerical or hardware limitation—and establish the minimum local Hilbert-space structure required for disorder-free quantum simulators to faithfully emulate localization physics.