Dresden 2026 – scientific programme
Parts | Days | Selection | Search | Updates | Downloads | Help
TT: Fachverband Tiefe Temperaturen
TT 75: Many-body Quantum Dynamics I (joint session DY/TT)
TT 75.4: Talk
Thursday, March 12, 2026, 10:15–10:30, HÜL/S186
Revisiting boundary-driven method for transport: Finite-size effects and the role of system-bath coupling — •Mariel Kempa1, Markus Kraft1, Sourav Nandy2, Jacek Herbrych3, Jiaozi Wang1, Jochen Gemmer1, and Robin Steinigeweg1 — 1University of Osnabrueck, Osnabrueck, Germany — 2Max Planck Institute for the Physics of Complex Systems, Dresden, Germany — 3Wroclaw University of Science and Technology, Wroclaw, Poland
Understanding transport in interacting quantum many-body systems is a central challenge in condensed matter and statistical physics. Numerical studies typically rely on two main approaches: Dynamics of linear-response functions in closed systems and Markovian dynamics governed by master equations for boundary-driven open systems. While the equivalence of their dynamical behavior has been explored in recent studies, a systematic comparison of the transport coefficients obtained from these two classes of methods remains an open question. Here, we address this gap by comparing and contrasting the dc diffusion constant Ddc computed from the aforementioned two approaches. We find a clear mismatch between the two, with Ddc exhibiting a strong dependence on the system-bath coupling for the boundary-driven technique, highlighting fundamental limitations of such a method in calculating the transport coefficients related to asymptotic dynamical behavior of the system. We trace the origin of this mismatch to the incorrect order of limits of time t → ∞ and system size L→ ∞, which we argue to be intrinsic to boundary-driven setups.
Keywords: many-body quantum systems; spin chains; quantum transport; open quantum systems; Lindblad equation