Quantum 2025 – scientific programme
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MON: Monday Contributed Sessions
MON 11: Quantum Transport I
MON 11.3: Talk
Monday, September 8, 2025, 14:45–15:00, ZHG104
Boundary-driven magnetization transport in the spin-1/2 XXZ chain and the role of the system-bath coupling strength — •Mariel Kempa1, Markus Kraft1, Sourav Nandy2, Jacek Herbrych3, Jiaozi Wang1, Jochen Gemmer1, and Robin Steinigeweg1 — 1University of Osnabrueck, D-49076 Osnabrueck, Germany — 2Max Planck Institute for Physics of Complex Systems, D-01187 Dresden, Germany — 3Wroclaw University of Science and Technology, 50-370 Wroclaw, Poland
We revisit the Lindblad equation in the context of boundary-driven magnetization transport in integrable spin-1/2 XXZ chain. In particular, we explore the influence of the system-bath coupling strength γ on the quantitative value of the diffusion constant D. Employing numerical simulations on the basis of stochastic unraveling and time-evolving block decimation, we obtain the curve D(γ) for finite system sizes, yet outside the range of exact diagonalization. We unveil that D(γ), as extracted from the steady state, depends significantly on γ and disagrees with the Kubo formula. We suggest a physical explanation of this disagreement.
Keywords: spin systems; spin chains; correlation functions; Lindblad equation; quantum transport