Ruben Burkard

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Currently, there is a scarcity of theoretical methods to calculate dynamical correlation functions at finite temperatures in frustrated spin systems. To address this challenge, we extend the well- established method of high-temperature expansion to the dynamical two-point Matsubara Green’s function, which we calculate to high order in perturbation theory. We consider Heisenberg models with one coupling constant J, arbitrary spin length, and without external magnetic field. We use resummation techniques to extrapolate our results to temperatures down to about T ≈ 0.2J. Our method gives an analytical expression for the frequency dependence, enabling analytical continuation to real frequencies. Using the dynamical information of the Matsubara correlator, we aim to study spin-liquid phases with this approach in the future.

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Uni Tübingen
0.03
Contact: Urban Seifert