arXiv subjects

Hyeon Jung Kim

Publications and source records attributed to Hyeon Jung Kim.

5 recordsLinked to original sources

arXiv2026

Non-Perturbative Renormalization Group for Ising-Nematic Criticality: A Closed-Form Nonlocal Ansatz

The two-dimensional metallic quantum critical problem is a long-standing puzzle that is widely believed to hold the key to resolving ubiquitous non-Fermi liquid behavior in strongly correlated electronic systems. In this study, we present a non-perturbative renormalization group (RG) analysis of the metallic Ising-nematic quantum critical point in two dimensions, formulated directly around an intrinsically nonlocal infrared (IR) boson propagator. Rather than treating the anomalous dynamical critical exponent $a$ as a fixed phenomenological parameter, we regard it as an intrinsic component of the fixed-point data to be determined from the internal consistency of the low-energy patch field theory under highly anisotropic scaling dimensions ($[k_0]=a+1$, $[k_x]=2$, $[k_y]=1$). While the leading two-loop diagrammatics vanish identically due to kinematic pole configurations, our three-loop evaluation reveals a profound structural asymmetry between the sectors: the fermion self-energy and Yukawa vertex receive non-vanishing logarithmic corrections, whereas the corresponding bosonic counter-term remains strictly zero. Consequently, we find that no self-consistent, intersecting fixed-point solution for the exponent $a$ exists within the three-loop truncation, failing to reproduce the physical value of $a \approx 1.85$ observed in quantum Monte Carlo simulations. We conjecture that the cross-linked topology of the four-loop boson self-energy diagrams is exactly marginal and yields the minimal, mandatory bosonic counter-term required to restore multi-sector self-consistency. Our framework establishes a rigid multi-loop matching scheme necessary to uniquely pin down the critical exponent, and uncovers a stable phase space for field anomalous dimensions.

cond-mat.str-el↗

arXiv2026

Taming the 3D Wilson-Fisher Fixed Point via Nonlocal Effective Action

We present a Renormalization Group (RG) framework based on a nonlocal effective action ansatz to analyze the strong coupling dynamics of the three-dimensional relativistic $ϕ^{4}$ theory. By implementing a Hubbard-Stratonovich transformation, we decouple the quartic interaction into the primary field $ϕ$ and an auxiliary field $φ\sim ϕ^2$, allowing both exponents $Δ_ϕ$ and $Δ_φ$ to act as independent, unconstrained variables rather than fixed scaling dimensions. Within this nonlocal propagator framework, both the field self-energies and vertex corrections are evaluated at the one-loop order. The resulting one-loop logarithmic derivatives determine the renormalization group flows of the couplings and the scaling exponents. For $d=3$ and $ε\approx-0.198$, the self-consistent equations yield a representative fixed point at $Δ_ϕ\approx0.97714$, $Δ_φ\approx-0.65260$, and $Δ_{ϕ^2}\approx1.04573$, corresponding to $η_ϕ\approx0.04572$ and $ν\approx0.51170$. Relative to the high-precision conformal-bootstrap benchmarks, the deviations are approximately $0.48\%$ for $Δ_ϕ$, $25.97\%$ for $Δ_{ϕ^2}$, and $18.77\%$ for $ν$, demonstrating sub-percent agreement in the fundamental-field sector while revealing substantially larger deviations in the composite and correlation-length sectors within the leading-order truncation.

cond-mat.str-el↗

arXiv2026

Emergent $\text{AdS}_{d+1}$ Geometry from Functional Renormalization Group via Bulk Metric Reconstruction

We present a holographic dual description for the O(N) vector model in $d$-dimensional Euclidean space within the functional renormalization group (FRG) framework. By iterating Wilsonian renormalization group transformations, the extra-dimensional scale coordinate is identified as the radial direction of an emergent $(d+1)$-dimensional bulk spacetime. We construct a bidirectional holographic dictionary in which the emergent bulk metric is determined by the spectrum of the non-perturbative $GG$ polarization function. Using this dictionary we show that as the mass gap decreases, the emergent geometry evolves from a Ricci flat to an Anti-de Sitter $(AdS_{d+1})$ geometry.

hep-th↗

arXiv2024

Holographic dual effective field theory in the Luttinger-Ward functional approach: Application to an SYK model

We construct an emergent holographic dual description in the Luttinger-Ward functional approach, where the renormalization group (RG) flows of collective bi-local fields appear manifestly in the bulk effective action with an emergent extra dimension. This holographic dual effective field theory reproduces $1/N$ quantum corrections in a self-consistent manner when we take the UV limit in the bulk effective action. Going into the IR regime in the extra dimension, we observe that a partial class of the field theoretic $1/N$, $1/N^{2}$, ... quantum corrections are resummed in the all-loop order and reorganized to form a holographic dual effective field theory in a large $N$ fashion living on the one-higher dimensional spacetime. In this study, we apply this theoretical framework into an Sachdev-Ye-Kitaev (SYK) model. Taking the large $N$ limit in the holographic dual effective field theory, we obtain nonlinearly coupled second-order bulk differential equations of motion for the three bi-local order-parameter fields of fermion self-energy, Green's function, and polarization function. Here, both UV and IR boundary conditions are derived self-consistently from the boundary effective action. We solve these highly intertwined nonlinear differential equations based on the so called matching method. Our ansatz for the bi-local order-parameter fields coincide with the conformally invariant solution of the field theoretic large $N$ limit in the UV limit, but their overall coefficients $RG-flow$ along the extra dimensional space, respectively, reflecting effects of higher-order quantum corrections. As a result, we find an insulating behavior, where the self-energy diverges at IR. ...

hep-th↗

arXiv2023

Microscopic origin of local electric polarization in NiPS$_3$

Recently, Zhang-Rice triplet to singlet excitations have been measured experimentally and verified numerically in a van der Waals antiferromagnet NiPS\textsubscript{3}, which reveals a collective local change of an electronic structure. In particular, such numerical simulations predicted that these electronic excitations occur simultaneously with local electric polarizations. In this study, we uncover the microscopic origin of this local electric polarization in the Zhang-Rice triplet to singlet excitation. Our lattice-model calculation predicts that the electric polarization can be controlled by applied magnetic fields, where the atomic spin-orbit coupling plays an important role. We speculate emergence of real space Berry curvature to describe the electric polarization in this strongly correlated system.

cond-mat.str-el↗