Ghost rotationally invariant slave-boson approach to response functions
Abstract
We propose a finite-temperature Gaussian-fluctuation formalism for response functions within ghost rotationally invariant slave-boson (gRISB) theory and apply it to the two-dimensional Hubbard model. The gRISB magnetic phase boundary and static spin and charge susceptibilities capture the trends of dynamical mean-field theory (DMFT), significantly improving upon standard RISB and the random phase approximation (RPA). At the RISB level, our formalism recovers the Kotliar-Ruckenstein response. The dynamical susceptibilities resolve paramagnons, low-energy sound modes, and high-energy Hubbard excitations. Because they are evaluated directly on the real-frequency axis, the results avoid Matsubara truncation, stochastic sampling, and numerical analytic continuation. We also introduce a conserving quasiparticle approximation that expresses the response in terms of dressed Green's functions and vertex corrections.
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BibTeX
@misc{lee2026ghost,
title = {{Ghost rotationally invariant slave-boson approach to response functions}},
author = {Tsung-Han Lee and Corey Melnick and Nicola Lanatà and Gabriel Kotliar},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.08575},
eprint = {2610.08575},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.08575},
}
RIS
TY - UNPB
TI - Ghost rotationally invariant slave-boson approach to response functions
AU - Tsung-Han Lee
AU - Corey Melnick
AU - Nicola Lanatà
AU - Gabriel Kotliar
PY - 2026
DA - 2026/10/07
PB - arXiv
DO - 10.48550/arxiv.2610.08575
UR - https://arxiv.org/abs/2610.08575
AB - We propose a finite-temperature Gaussian-fluctuation formalism for response functions within ghost rotationally invariant slave-boson (gRISB) theory and apply it to the two-dimensional Hubbard model. The gRISB magnetic phase boundary and static spin and charge susceptibilities capture the trends of dynamical mean-field theory (DMFT), significantly improving upon standard RISB and the random phase approximation (RPA). At the RISB level, our formalism recovers the Kotliar-Ruckenstein response. The dynamical susceptibilities resolve paramagnons, low-energy sound modes, and high-energy Hubbard excitations. Because they are evaluated directly on the real-frequency axis, the results avoid Matsubara truncation, stochastic sampling, and numerical analytic continuation. We also introduce a conserving quasiparticle approximation that expresses the response in terms of dressed Green's functions and vertex corrections.
ER -