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TT: Fachverband Tiefe Temperaturen

TT 69: Nonequilibrium Quantum Systems II (joint session TT/DY)

TT 69.5: Talk

Thursday, March 21, 2024, 10:30–10:45, H 3025

Constructing nonequilibrium steady states from equilibrium correlation functions in generic nonintegrable systems — •Markus Kraft¹, Jonas Richter^2,3, Fengping Jin⁴, Sourav Nandy⁵, Zala Lenarčič⁵, Jacek Herbrych⁶, Kristel Michielsen⁴, Hans De Raedt⁷, Jochen Gemmer¹, and Robin Steinigeweg¹ — ¹U Osnabrück — ²U Stanford — ³U Hannover — ⁴FZ Jülich — ⁵U Ljubljana — ⁶U Wroclaw — ⁷U Groningen

State-of-the-art approaches to extract transport coefficients of manybody quantum systems broadly fall into two categories: (i) they target the linear-response regime in terms of equilibrium correlation functions of the closed system; or (ii) they consider an open-system situation typically modeled by a Lindblad equation, where a nonequilibrium steady state emerges from driving the system at its boundaries. While quantitative agreement between (i) and (ii) has been found for selected model and parameter choices, also disagreement has been pointed out in the literature. Studying magnetization transport in the spin-1/2 XXZ chain, we here demonstrate that at weak driving the nonequilibrium steady state in an open system, including its buildup in time, can remarkably be constructed just on the basis of correlation functions in the closed system. We numerically illustrate this direct correspondence of closed-system and open-system dynamics.

[1] T. Heitmann et al., arXiv:2303.00430

[2] T. Heitmann et al., Phys. Rev. E 108 (2023) 024102

[3] M. Kraft et al., in preparation

Keywords: quantum transport; spin systems; correlation function; open systems; Lindblad equation