Sep 20 – 25, 2026
University of Graz
Europe/Vienna timezone

Quantum Fisher information in a strange metal

Sep 23, 2026, 4:30 PM
30m
HS 15.14 (University of Graz)

HS 15.14

University of Graz

15 - RESOWI E, 1st floor
4) Invited talk M06 - Interaction effects in correlated systems with higher-order Van Hove singularities and flat bands Mini-Colloquium

Speaker

Federico Mazza (TU Wien)

Description

Strange metal behavior emerges across a wide range of material platforms and remains a central open problem in correlated quantum matter [1]. Beyond the hallmark linear-in-temperature electrical resistivity, it is characterized by entropy accumulation, a discontinuous change in Fermi volume, and energy-over-temperature scaling in dynamical susceptibilities [2]. Recent studies suggest that kagome metals, hosting flat electronic bands near the Fermi level, can exhibit magnetic-field-tunable strange metal behavior even in the absence of f electrons [3]. The heavy fermion compound Ce3Pd20Si6 provides an ideal platform to investigate quantum criticality beyond the Landau–Ginzburg–Wilson framework, including access to fractional critical exponents and emerging concepts such as multipartite entanglement [4,5]. Here, we present inelastic neutron scattering measurements at a strange-metal quantum critical point in Ce3Pd20Si6. Our analysis reveals dynamical scaling behavior, quantifies the entanglement depth via the quantum Fisher information density fQ, and establishes a direct comparison with quantum Monte Carlo simulations. These results highlight intriguing connections between heavy-fermion systems and flat-band materials [3,6].

[1] Checkelsky, J. G., et al. Flat bands, strange metals, and the Kondo effect, Nat. Rev. Mater. 9, 509–526 (2024).
[2] Paschen, S. & Si, Q. Quantum phases driven by strong correlations, Nat. Rev. Phys. 3, 9–26 (2021).
[3] Ye, L., et al. Hopping frustration-induced flat band and strange metallicity in a kagome metal. Nat. Phys. 20, 610–614 (2024).
[4] Martelli, V., et al. Sequential localization of a complex electron fluid, Proc. Natl. Acad. Sci. U.S.A. 116, 17701 (2019).
[5] Hauke, P., et al. Measuring multipartite entanglement through dynamic susceptibilities, Nat. Phys. 12, 778–782 (2016).
[6] Mazza, F., Biswas, S., et al. Quantum Fisher information in a strange metal, arXiv:2403.12779 to appear in Nat. Phys. (2026).

Authors

Federico Mazza (TU Wien) Dr Sounak Biswas (Institut für Theoretische Physik und Astrophysik, Universität Würzburg, 97074 Würzburg, Germany)

Co-authors

Prof. Andrey Prokofiev (TU Wien) Prof. Fakher Assaad (Institut für Theoretische Physik und Astrophysik, Universität Würzburg, 97074 Würzburg, Germany) Dr Paul Steffens (Institut Laue-Langevin, 71 Ave Martyrs, 38042 Grenoble, France) Prof. Qimiao Si (Department of Physics and Astronomy, Center for Quantum Materials, 6100 Main Street, Rice University, Houston, Texas 77005, USA) Silke Paschen (Institute of Solid State Physics, TU Wien) Dr Xinlin Yan (TU Wien)

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