Localization and dynamical transitions in aperiodic quantum chains
Research into new materials involving intense magnetic fields and low temperatures
Using machine learning in the study of quantum phase transition
| Full text | |
| Author(s): |
Schliemann, John
;
Costa, Joao Vitor, I
;
Wenk, Paul
;
Egues, J. Carlos
Total Authors: 4
|
| Document type: | Journal article |
| Source: | PHYSICAL REVIEW B; v. 103, n. 17, p. 10-pg., 2021-05-13. |
| Abstract | |
We study the transitions between ergodic and many-body localized phases in spin systems, subject to quenched disorder, including the Heisenberg chain and the central spin model. In both cases systems with common spin lengths 1/2 and 1 are investigated via exact numerical diagonalization and random matrix techniques. Particular attention is paid to the sample-to-sample variance (Delta(s)r)(2) of the averaged consecutive-gap ratio < r > for different disorder realizations. For both types of systems and spin lengths we find a maximum in Delta(s)r as a function of disorder strength, accompanied by an inflection point of < r >, signaling the transition from ergodicity to many-body localization. The critical disorder strength is found to be somewhat smaller than the values reported in the recent literature. Further information about the transitions can be gained from the probability distribution of expectation values within a given disorder realization. (AU) | |
| FAPESP's process: | 16/08468-0 - Topological insulators and Majorana fermions |
| Grantee: | José Carlos Egues de Menezes |
| Support Opportunities: | Regular Research Grants |
| FAPESP's process: | 18/19017-4 - Many-body localization: central spin models |
| Grantee: | José Carlos Egues de Menezes |
| Support Opportunities: | Research Grants - Visiting Researcher Grant - International |
| FAPESP's process: | 20/00841-9 - Shubnikov-de-Haas oscillations in topological and non-topological electron systems |
| Grantee: | José Carlos Egues de Menezes |
| Support Opportunities: | Regular Research Grants |