Emergent thermalization thresholds in unitary dynamics of inhomogeneously disordered quantum systems
Year: 2025
Type: article
Abstract: Inspired by the avalanche scenario for many-body localization instability, we reverse the conventional setup and ask whether a large weakly disordered chain can thermalize a smaller, strongly disordered chain when the composite system evolves unitarily. Using transport as a dynamical probe, we identify three distinct thermalization regimes as a function of the disorder strength of the smaller chain: (i) complete thermalization with self-averaging at weak disorder, (ii) realization-dependent thermalization with strong sample-to-sample fluctuations at intermediate disorder, and (iii) absence of thermalization at strong disorder. We find that for a fixed length of the smaller chain, the non-self-averaging regime broadens with the size of the weakly disordered chain, revealing a nuanced interplay between disorder and system size. These results highlight how inhomogeneous disorder can induce emergent thermalization thresholds in closed quantum systems, providing direct access to disorder regimes where thermalization or its absence can be reliably observed.
Source: Physical review. E
DOI: 10.1103/ycdx-sd5m
Authors: Soumya Kanti Pal, C. L. Sriram, Shamik Gupta
Institution: Tata Institute of Fundamental Research
Language: English
Topic: Quantum many-body systems
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W4417247666