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|Abstract:||We provide a systematic comparison of the many-body localization (MBL) transition in spin chains with nonrandom quasiperiodic versus random fields. We find evidence suggesting that these belong to two separate universality classes: the first dominated by “intrinsic” intrasample randomness, and the second dominated by external intersample quenched randomness. We show that the effects of intersample quenched randomness are strongly growing, but not yet dominant, at the system sizes probed by exact-diagonalization studies on random models. Thus, the observed finite-size critical scaling collapses in such studies appear to be in a preasymptotic regime near the nonrandom universality class, but showing signs of the initial crossover towards the external-randomness-dominated universality class. Our results provide an explanation for why exact-diagonalization studies on random models see an apparent scaling near the transition while also obtaining finite-size scaling exponents that strongly violate Harris-Chayes bounds that apply to disorder-driven transitions. We also show that the MBL phase is more stable for the quasiperiodic model as compared to the random one, and the transition in the quasiperiodic model suffers less from certain finite-size effects.|
|Electronic Publication Date:||18-Aug-2017|
|Citation:||Khemani, Vedika, Sheng, DN, Huse, David A. (2017). Two Universality Classes for the Many-Body Localization Transition. PHYSICAL REVIEW LETTERS, 119 (10.1103/PhysRevLett.119.075702|
|Type of Material:||Journal Article|
|Journal/Proceeding Title:||PHYSICAL REVIEW LETTERS|
|Version:||Final published version. Article is made available in OAR by the publisher's permission or policy.|
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