From Quantum to Classical Dissipative Spin Dynamics

@misc{ataei2026from,
  title = {{From Quantum to Classical Dissipative Spin Dynamics}},
  author = {Alireza Ataei and Leila Ataei and Olle Eriksson and Vahid Azimi Mousolou},
  howpublished = {arXiv},
  year = {2026},
  month = sep,
  doi = {10.48550/arxiv.2609.35112},
  eprint = {2609.35112},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2609.35112},
}

TY  - UNPB
TI  - From Quantum to Classical Dissipative Spin Dynamics
AU  - Alireza Ataei
AU  - Leila Ataei
AU  - Olle Eriksson
AU  - Vahid Azimi Mousolou
PY  - 2026
DA  - 2026/09/28
PB  - arXiv
DO  - 10.48550/arxiv.2609.35112
UR  - https://arxiv.org/abs/2609.35112
AB  - The Landau-Lifshitz-Gilbert (LLG) equation provides the fundamental description of dissipative magnetization dynamics. A recently proposed quantum analog, the quantum Landau-Lifshitz-Gilbert (QLLG) equation, extends this framework to quantum spin systems. However, whether the QLLG equation recovers the LLG equation in the classical large-spin limit for interacting spin systems remains an open question. Here, we demonstrate this connection by deriving the LLG equation as the classical large-spin limit of the QLLG equation. We establish this correspondence analytically and verify it numerically for an interacting spin system. These results provide a quantum-to-classical description of dissipative spin dynamics, offering a microscopic foundation for the LLG equation. From numerical calculations provided here, we also conclude that quantum effects become much less noticeable for systems with larger number of spins in the Hamiltonian.
ER  -