Low-frequency behavior of off-diagonal matrix elements in the integrable XXZ chain and in a locally perturbed quantum-chaotic XXZ chain
Citation:
Brenes, M., Goold, J., Rigol, M., Low-frequency behavior of off-diagonal matrix elements in the integrable XXZ chain and in a locally perturbed quantum-chaotic XXZ chain, Physical Review B, 2020, 102, 075127Abstract:
We study the matrix elements of local operators in the eigenstates of the integrable XXZ chain and of the quantum-chaotic model obtained by locally perturbing the XXZ chain with a magnetic impurity. We show that, at frequencies that are polynomially small in the system size, the behavior of the variances of the off-diagonal matrix elements can be starkly different depending on the operator. In the integrable model we find that, as the frequency ω→0, the variances are either nonvanishing (generic behavior) or vanishing (for a special class of operators). In the quantum-chaotic model, on the other hand, we find the variances to be nonvanishing as ω→0 and to indicate diffusive dynamics. We highlight which properties of the matrix elements of local operators are different between the integrable and quantum-chaotic models independently of the specific operator selected.
Sponsor
Grant Number
Science Foundation Ireland
Author's Homepage:
http://people.tcd.ie/gooldj
Author: Goold, John
Type of material:
Journal ArticleCollections
Series/Report no:
Physical Review B;102;
7;
Availability:
Full text availableKeywords:
nonvanishing as ω→0, integrable XXZ chain, quantum-chaotic model, 1-dimensional spin chains, Quantum chaos, Nonequilibrium statistical mechanics, Eigenstate thermalizationDOI:
http://dx.doi.org/10.1103/PhysRevB.102.075127Metadata
Show full item recordLicences: