Eigenstate thermalization hypothesis beyond standard indicators : Emergence of random-matrix behavior at small frequencies

Using numerical exact diagonalization, we study matrix elements of a local spin operator in the eigenbasis of two different nonintegrable quantum spin chains. Our emphasis is on the question to what extent local operators can be represented as random matrices and, in particular, to what extent matrix elements can be considered as uncorrelated. As a main result, we show that the eigenvalue distribution of band submatrices at a fixed energy density is a sensitive probe of the correlations between matrix elements. We find that, on the scales where the matrix elements are in a good agreement with all standard indicators of the eigenstate thermalization hypothesis, the eigenvalue distribution still exhibits clear signatures of the original operator, implying correlations between matrix elements. Moreover, we demonstrate that at much smaller energy scales, the eigenvalue distribution approximately assumes the universal semicircle shape, indicating transition to the random-matrix behavior, and in particular that matrix elements become uncorrelated.

Medienart:

E-Artikel

Erscheinungsjahr:

2020

Erschienen:

2020

Enthalten in:

Zur Gesamtaufnahme - volume:102

Enthalten in:

Physical review. E - 102(2020), 4-1 vom: 25. Okt., Seite 042127

Sprache:

Englisch

Beteiligte Personen:

Richter, Jonas [VerfasserIn]
Dymarsky, Anatoly [VerfasserIn]
Steinigeweg, Robin [VerfasserIn]
Gemmer, Jochen [VerfasserIn]

Links:

Volltext

Themen:

Journal Article

Anmerkungen:

Date Revised 20.11.2020

published: Print

Citation Status PubMed-not-MEDLINE

doi:

10.1103/PhysRevE.102.042127

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM317796917