SKM 2023 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 43: Poster: Correlated Electrons II

TT 43.20: Poster

Mittwoch, 29. März 2023, 15:00–18:00, P2/OG3

Spatiotemporal dynamics of classical and quantum density profiles in low-dimensional spin systemsTjark Heitmann1, Jonas Richter2, Fengping Jin3, Kristel Michielsen3, Hans De Raedt4, and •Robin Steinigeweg11University of Osnabrück, DE — 2University College London, UK — 3FZ Jülich, DE — 4University of Groningen, NL

We provide a detailed comparison between the dynamics of high-temperature spatiotemporal correlation functions in quantum and classical spin models. In the quantum case, our large-scale numerics are based on the concept of quantum typicality, which exploits the fact that random pure quantum states can faithfully approximate ensemble averages, allowing the simulation of up to 40 spin-1/2 spins. Due to the exponentially growing Hilbert space, we find that for such system sizes even a single random state is sufficient to yield results with extremely low noise. In contrast, a classical analog of typicality is missing. In particular, in order to obtain data with a similar level of noise in the classical case, extensive averaging over classical trajectories is required, no matter how large the system size. Focusing on (quasi-)one-dimensional spin chains and ladders, we find a remarkably good agreement between quantum and classical dynamics. Comparing space-time profiles of the spin and energy correlation functions, the agreement is found to hold not only in the bulk but also in the tails of the resulting density distribution. The mean-squared displacement of the density profiles is found to exhibit similar scaling for quantum and classical models.

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