Intricately Entangled Spin and Charge Diffusion and the Coherence-Incoherence Crossover in the High-Dimensional Hubbard Model

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Hauptverfasser: Prakash, Gopal, Hassan, S. R., Laad, M. S., Vidhyadhiraja, N. S., Ramakrishnan, T. V.
Format: Preprint
Veröffentlicht: 2025
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author Prakash, Gopal
Hassan, S. R.
Laad, M. S.
Vidhyadhiraja, N. S.
Ramakrishnan, T. V.
author_facet Prakash, Gopal
Hassan, S. R.
Laad, M. S.
Vidhyadhiraja, N. S.
Ramakrishnan, T. V.
contents Correlation-driven metal-insulator transitions and temperature-driven quantum-coherent-to-incoherent crossovers in correlated electron systems underpin the doping, temperature and frequency-resolved evolution of physical responses. Motivated by recent experimental studies that investigate the evolution of dynamical spin and charge responses, we analyze the spin and charge diffusion spectra in both half-filled and doped one-band Hubbard model using Dynamical Mean Field Theory (DMFT) combined with the Numerical Renormalization Group (NRG). We compare the relative strengths and limitations of Density Matrix NRG (DMNRG) and Full Density Matrix NRG (FDM-NRG) in capturing low-frequency spectral features and their evolution with temperature, interaction strength and band-filling. Key measures, including characteristic frequency scales, Kullback-Leibler divergence, diffusion constants, and kurtosis provide complementary but internally consistent picture for the evolution of spin and charge excitations across bandwidth as well as the band-filling driven Mott transitions and the coherent-incoherent crossover. We find that spin and charge fluctuations cross over from quantum-coherent-to-quantum-incoherent at distinct temperatures, providing a microscopic insight into the complex, two-stage, Fermi-to-non-Fermi liquid-to-bad metal crossovers seen in transport data, in particular in the $dc$ resistivity.
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id arxiv_https___arxiv_org_abs_2501_08121
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Intricately Entangled Spin and Charge Diffusion and the Coherence-Incoherence Crossover in the High-Dimensional Hubbard Model
Prakash, Gopal
Hassan, S. R.
Laad, M. S.
Vidhyadhiraja, N. S.
Ramakrishnan, T. V.
Strongly Correlated Electrons
Correlation-driven metal-insulator transitions and temperature-driven quantum-coherent-to-incoherent crossovers in correlated electron systems underpin the doping, temperature and frequency-resolved evolution of physical responses. Motivated by recent experimental studies that investigate the evolution of dynamical spin and charge responses, we analyze the spin and charge diffusion spectra in both half-filled and doped one-band Hubbard model using Dynamical Mean Field Theory (DMFT) combined with the Numerical Renormalization Group (NRG). We compare the relative strengths and limitations of Density Matrix NRG (DMNRG) and Full Density Matrix NRG (FDM-NRG) in capturing low-frequency spectral features and their evolution with temperature, interaction strength and band-filling. Key measures, including characteristic frequency scales, Kullback-Leibler divergence, diffusion constants, and kurtosis provide complementary but internally consistent picture for the evolution of spin and charge excitations across bandwidth as well as the band-filling driven Mott transitions and the coherent-incoherent crossover. We find that spin and charge fluctuations cross over from quantum-coherent-to-quantum-incoherent at distinct temperatures, providing a microscopic insight into the complex, two-stage, Fermi-to-non-Fermi liquid-to-bad metal crossovers seen in transport data, in particular in the $dc$ resistivity.
title Intricately Entangled Spin and Charge Diffusion and the Coherence-Incoherence Crossover in the High-Dimensional Hubbard Model
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2501.08121