Hamiltonian Inference from Dynamical Excitations in Confined Quantum Magnets
Journal article, 2023

Quantum-disordered models provide a versatile platform to explore the emergence of quantum excitations in many-body systems. The engineering of spin models at the atomic scale with scanning tunneling microscopy and the local imaging of excitations with electrically driven spin resonance has risen as a powerful strategy to image spin excitations in finite quantum spin systems. Here, focusing on S = 1/2 lattices as realized by Ti in MgO, we show that dynamical spin excitations provide a robust strategy to infer the nature of the underlying Hamiltonian. We show that finite-size interference of the dynamical many-body spin excitations of a generalized long-range Heisenberg model allows the underlying spin couplings to be inferred. We show that the spatial distribution of local spin excitations in Ti islands and ladders directly correlates with the underlying ground state in the thermodynamic limit. Using a supervised-learning algorithm, we demonstrate that the different parameters of the Hamiltonian can be extracted by providing the spatially dependent and frequency-dependent local excitations that can be directly measured by electrically driven spin resonance with scanning tunneling microscopy. Our results put forward local dynamical excitations in confined quantum spin models as versatile witnesses of the underlying ground state, providing an experimentally robust strategy for Hamiltonian inference in complex real spin models.

Author

Netta Karjalainen

University of Helsinki

Aalto University

Zina Lippo

University of Helsinki

Aalto University

Guangze Chen

Chalmers, Microtechnology and Nanoscience (MC2), Applied Quantum Physics

Rouven Koch

Aalto University

Adolfo O. Fumega

Aalto University

Jose L. Lado

Aalto University

Physical Review Applied

2331-7019 (eISSN)

Vol. 20 2 024054

Subject Categories

Other Physics Topics

Condensed Matter Physics

DOI

10.1103/PhysRevApplied.20.024054

More information

Latest update

7/31/2024