Description: Exponential damping induced by random and realistic perturbations

This title appears in the Scientific Report : 2020

Exponential damping induced by random and realistic perturbations

Given a quantum many-body system and the expectation-value dynamics of some operator, we study how this reference dynamics is altered due to a perturbation of the system's Hamiltonian. Based on projection operator techniques, we unveil that if the perturbation exhibits a random-matrix structure...

Personal Name(s):	Richter, Jonas (Corresponding author)
	Jin, Fengping / Knipschild, Lars / De Raedt, Hans / Michielsen, Kristel / Gemmer, Jochen / Steinigeweg, Robin
Contributing Institute:	Jülich Supercomputing Center; JSC JARA - HPC; JARA-HPC
Published in:	Physical Review E Physical review / E, 101 101 (2020 2020) 6 6, S. 062133 062133
Imprint:	Woodbury, NY Inst. 2020 2020-06-19 2020-06-01
DOI:	10.1103/PhysRevE.101.062133
PubMed ID:	32688487
Document Type:	Journal Article
Research Program:	Manipulation and dynamics of quantum spin systems Computational Science and Mathematical Methods
Link:	OpenAccess OpenAccess
	Publikationsportal JuSER

Please use the identifier: http://dx.doi.org/10.1103/PhysRevE.101.062133 in citations.
Please use the identifier: http://hdl.handle.net/2128/25981 in citations.

Given a quantum many-body system and the expectation-value dynamics of some operator, we study how this reference dynamics is altered due to a perturbation of the system's Hamiltonian. Based on projection operator techniques, we unveil that if the perturbation exhibits a random-matrix structure in the eigenbasis of the unperturbed Hamiltonian, then this perturbation effectively leads to an exponential damping of the original dynamics. Employing a combination of dynamical quantum typicality and numerical linked cluster expansions, we demonstrate that our theoretical findings for random matrices can, in some cases, be relevant for the dynamics of realistic quantum many-body models as well. Specifically, we study the decay of current autocorrelation functions in spin-1/2 ladder systems, where the rungs of the ladder are treated as a perturbation to the otherwise uncoupled legs. We find a convincing agreement between the exact dynamics and the lowest-order prediction over a wide range of interchain couplings.