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  • Letter
  • Open Access

Entanglement in the pseudogap regime of cuprate superconductors

Frederic Bippus1, Juraj Krsnik1,2, Motoharu Kitatani3, Luka Akšamović1, Anna Kauch1, Neven Barišić1,4, and Karsten Held1

  • 1Institute of Solid State Physics, TU Wien, A-1040 Vienna, Austria
  • 2Department for Research of Materials under Extreme Conditions, Institute of Physics, HR-10000 Zagreb, Croatia
  • 3Department of Material Science, University of Hyogo, Ako, Hyogo 678-1297, Japan
  • 4Department of Physics, Faculty of Science, University of Zagreb, Bijenička 32, HR-10000 Zagreb, Croatia

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Phys. Rev. B 112, L081110 – Published 20 August, 2025

DOI: https://doi.org/10.1103/xk42-b9cx

Abstract

We find a strongly enhanced entanglement within the pseudogap regime of the Hubbard model. This entanglement is estimated from the quantum Fisher information and, avoiding the ill-conditioned analytical continuation, the quantum variance. Both are lower bounds for the actual entanglement and can be calculated from the (antiferromagnetic) susceptibility, obtained here with the dynamical vertex approximation. Our results qualitatively agree with experimental neutron scattering experiments for various cuprates. Theory predicts a ln(1/T) divergence of the entanglement for low temperatures T, which is however cut off by the onset of superconductivity.

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Phys. Rev. B 112, L081110– Published 20 August, 2025
  • Received 30 April 2025
  • Revised 14 July 2025
  • Accepted 30 July 2025
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