Aleksandrs Zacinskis

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Dynamical Mean-Field Theory (DMFT) has become a powerful tool for studying materials with correlated electrons. However, most DMFT solvers operate on imaginary Matsubara frequencies, making the extraction of accurate spectral functions challenging due to the need for analytical continuation. Here, we perform DMFT calculations using a real-frequency solver implemented in Quanty. This implementation utilizes a one-particle basis of natural impurity orbitals [1] to investigate correlated model systems with local interactions. We systematically study the Hubbard model, focusing on the critical interaction strength for the metal–insulator transition and the chemical potential as a function of filling, while comparing different bath discretization strategies and numerical cutoffs that control the Hilbert space size. In addition, we compare the Dyson equation and equations-of-motion methods for calculating the self-energy and analyze the impact of finite broadening in the self-consistency loop. Our results demonstrate robust and satisfactory convergence at moderate computational costs, validating the reliability of this approach. All calculations were performed using the open-source quantum many-body code Quanty (www.quanty.org), emphasizing its accessibility for broader applications in correlated electron systems.
[1] Phys. Rev. B 90, 085102 (2014)

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Heidelberg University
0.03
Contact: Fabian Kugler