Dzyaloshinskii-Moriya and dipole-dipole interactions affect coupling-based Landau-Majorana-St\"uckelberg-Zener transitions

TL;DR

This paper explores how Dzyaloshinskii-Moriya and dipole-dipole interactions influence Landau-Majorana-Stückelberg-Zener transitions in coupled spins, revealing their independent effects on quantum dynamics and potential for characterizing spin interactions.

Contribution

It extends the LMSZ transition model to include DM and dipole-dipole interactions, providing an exact treatment and insights into their roles in quantum dynamics.

Findings

DM and d-d interactions independently modify the LMSZ transition dynamics.

Measurement of magnetization evolution can determine the relative strengths of couplings.

The enriched Hamiltonian maintains C2-symmetry, enabling exact solutions.

Abstract

It has been theoretically demonstrated that two spins (qubits or qutrits), coupled by exchange interaction only, undergo a coupling-based joint Landau-Majorana-St\"uckelberg-Zener (LMSZ) transition when a linear ramp acts upon one of the two spins. Such a transition, under appropriate conditions on the parameters, drives the two-spin system toward a maximally entangled state. In this paper, effects on the quantum dynamics of the two qudits, stemming from the Dzyaloshinskii-Moriya (DM) and dipole-dipole (d-d) interactions, are investigated qualitatively and quantitatively. The enriched Hamiltonian model of the two spins, shares with the previous microscopic one the same C2-symmetry which once more brings about an exact treatment of the new quantum dynamical problem. This paper transparently reveals that the DM and d-d interactions generate independent, enhancing or hindering, modifications in the dynamical behaviour predicted for the two spins coupled exclusively by the exchange interaction. It is worthy noticing that, on the basis of the theory here developed, the measurement of the time evolution of the magnetization in a controlled LMSZ scenario, can furnish information on the relative weights of the three kinds of couplings describing the spin system. This possibility is very important since it allows in principle to legitimate the choice of the microscopic model to be adopted in a given physical scenario.