arXiv subjects

Eunwoo Lee

Publications and source records attributed to Eunwoo Lee.

At least 19 recordsLinked to original sources

arXiv2026

MedVA: An End-to-End Neuro-Symbolic Agentic System for Medical Volume Visualization

Medical volume visualization requires selecting regions of interest (ROIs) and carefully controlling their relative visual emphasis according to a given clinical intent. Implementing these decisions in conventional workflows demands substantial clinical and visualization expertise and often involves trial-and-error optimization. Recent agentic systems have introduced natural-language interaction and autonomous visualization operations but largely rely on MLLM-based inference throughout the workflow. Although MLLMs encode broad medical knowledge and provide strong reasoning capabilities, such inference may be suboptimal for medical volume visualization, potentially leading to clinically incomplete interpretations of user requests and unreliable ROI identification and visualization optimization. In this work, we present MedVA, an end-to-end neuro-symbolic agentic system for medical volume visualization that addresses these limitations through three complementary agents. The neuro-symbolic intent formulation agent refines MLLM-based interpretations of natural-language requests through symbolic reasoning over established clinical knowledge, which provides more complete, clinically grounded ROI specifications than MLLM-only reasoning. The multi-model ROI identification agent directly identifies semantically specified ROIs in the original volume by leveraging complementary large-scale pretrained medical segmentation models. The objective-driven visualization optimization agent explicitly evaluates ROI visibility and occlusion in the original volume using a volume-based visibility objective. Extensive agent-level and system-level evaluations across diverse medical datasets and interaction scenarios support the effectiveness of the individual agents. A formative user study further indicates high usability and practical value among users with different levels of expertise.

cs.GR↗

arXiv2026

Matrix Theory from Holography

We propose a setup that embeds Matrix Theory for M-theory into the AdS/CFT correspondence, allowing the former to be tested using the latter. The central claim is a triality among the BMN matrix model of rank $m$, a large-charge monopole sector of ABJM theory with charge $J$, and M-theory on the maximally supersymmetric eleven-dimensional pp-wave with a compact lightlike direction. The relevant ABJM limit sends $N,k,J\to\infty$ while keeping $N/k^2$ and $m=J/k$ fixed. We provide quantitative evidence for this triality by showing that, in this triple-scaling limit, the ABJM superconformal index agrees precisely with a grand-canonical sum of Witten indices of the $U(m)$ BMN matrix model. This relation also yields a compact grand-canonical expression for the BMN index, which we use to revisit its large-$m$ behavior. Our analytic and numerical results reveal strong boson--fermion cancellations and show no evidence for the previously claimed $e^{O(m^2)}$ growth when the BMN charge scales as $Q \sim m^2$. We further study the correspondence between the BPS cohomologies of the two theories by constructing a letter-level dictionary. This leads to a new notion of BPS fortuity in ABJM theory that survives even at strict $N=\infty$: although the usual fortuity associated with finite-$N$ trace relations disappears in the triple-scaling limit, each fixed-monopole sector is governed by the effective rank $m$, and finite-$m$ trace relations generate fortuitous states that map directly to fortuitous states of the BMN matrix model. Finally, we discuss connections to related concepts such as large-charge matrix models, open--closed--open triality, and worldline holography.

hep-th↗

arXiv2026

Equilibrium Partition Function of Non-Relativistic CFTs in Harmonic Trap

We investigate the equilibrium partition function of non-relativistic conformal field theories in harmonic quantization. We first analyze the hydrodynamic regime and show that, at leading order, the partition function exhibits a universal structure determined by the equation of state: the logarithm of the partition function develops simple poles in $ω^2-Ω_a^2$, where $ω$ is the harmonic trapping frequency and $Ω_a$ are angular velocities acting as chemical potentials for angular momentum. The corresponding residue is determined by a single-variable function of $μ/T$, with $μ$ the particle-number chemical potential and $T$ the temperature. We then study the large-angular-momentum limit $Ω_a\toω$. In this regime centrifugal effects nearly cancel the trapping potential, and the logarithm of the partition function again exhibits simple poles in $ω^2-Ω_a^2$, but with a less universal residue depending separately on $μ/T$ and $ω/T$. As explicit examples we analyze superfluid systems realizable in cold-atom experiments, in particular fermions at unitarity confined in a harmonic trap.

hep-th↗

arXiv2026

BMN-like Matrix Models

We conjecture a family of matrix quantum mechanical models that are holographically dual to discrete light-cone quantization of M-theory in pp-wave-like backgrounds. These backgrounds can be obtained from a Penrose limit of AdS$_4\times X_7$, where $X_7$ is Einstein. The matrix models arise from a classically consistent dimensional reduction of the UV Lagrangians of $\mathcal{N}=1$ superconformal field theories, in close analogy with how the BMN matrix model is obtained by dimensional reduction from $\mathcal{N}=4$ super Yang-Mills theory. We also discuss about supersymmetric black objects in pp-wave background by studying the Witten index and speculate that the area of the horizon is bounded from above for a fixed $N$.

hep-th↗

arXiv2025

Konishi lifts a black hole

We investigate the \emph{quantum} cohomology of a supercharge $Q$ in $\mathcal{N}=4$ super Yang-Mills theory. Recent analyses have revealed a mismatch between the one-loop BPS spectra of the S-dual $SO(7)$ and $Sp(3)$ theories. The $SO(7)$ theory contains a pair of additional graviton (monotone) and non-graviton (fortuitous) cohomologies, whose net contributions cancel in the superconformal index. We show that the quantum-corrected $Q$, inferred from the generalized Konishi anomaly, pairs and lifts these extra cohomologies.

hep-th↗

arXiv2025

Supersymmetric Grey Galaxies, Dual Dressed Black Holes and the Superconformal Index

Motivated by the recent construction of grey galaxy and Dual Dressed Black Hole solutions in $AdS_5\times S^5$, we present two conjectures relating to the large $N$ entropy of supersymmetric states in ${\cal N}=4$ Yang-Mills theory. Our first conjecture asserts the existence of a large number of supersymmetric states which can be thought of as a non interacting mix of supersymmetric black holes and supersymmetric `gravitons'. It predicts a microcanonical phase diagram of supersymmetric states with eleven distinct phases, and makes a sharp prediction for the supersymmetric entropy (as a function of 5 charges) in each of these phases. The microcanonical version of the superconformal index involves a sum over states - with alternating signs - over a line in 5 parameter charge space. Our second (and more tentative) conjecture asserts that this sum is dominated by the point on the line that has the largest supersymmetric entropy. This conjecture predicts a large $N$ formula for the superconformal index as a function of indicial charges, and predicts a microcanonical indicial phase diagram with nine distinct phases. It predicts agreement between the superconformal index and black hole entropy in one phase (so over one range of charges), but disagreement in other phases (and so at other values of charges). We compare our predictions against numerically evaluated superconformal index at $N\leq10$, and find qualitative agreement.

hep-th↗

arXiv2025

Extremal AdS Black Holes as Fluids: A Matrix Large-Charge EFT Approach

We develop a simple, yet powerful, matrix-valued large-charge EFT that captures the thermodynamic behavior of rotating extremal large-charge AdS black holes. We introduce a minimal "matrix EFT" by promoting the complex scalar in large charge EFT to a complex $N\times N$ adjoint scalar, whose $O(N^2)$ modes contribute at zero temperature. Employing a mean-field approximation, we solve the self-consistency equations and obtain explicit rigidly rotating fluid solutions. We demonstrate that their energy, angular momenta, and charge densities exactly reproduce the thermodynamics and boundary stress tensor of zero-temperature conformal fluids. A microscopic mode-counting further accounts for the $O(N^2)$ entropy. Via the fluid/gravity correspondence, this fluid describes an extremal AdS black hole in large charge limit. We also comment on supersymmetric BPS black holes, which fall outside the usual hydrodynamic regime but nevertheless exhibit simple, universal behavior in the large angular momentum limit. In this regime, their non-linear charge-spin relations simplify to form reminiscent of our extremal fluid solutions at large angular momentum limit.

hep-th↗

arXiv2025

Probing Non-Graviton Spectra in $\mathcal{N}=4$ SYM via BMN truncation and S-Duality

The one-loop cohomology of N=4 SYM is conjectured to be isomorphic to the exact cohomology. As a result, its truncations are expected to be subrings of the exact cohomology. We study the superconformal index restricted over one such truncation known as the BMN truncation. We present a systematic algorithm to compute the BMN index using the method of residues. We compute the BMN index for SU(N) SYM for N = 2,...,6 in closed form. It is expressed as a rational function of the fugacity. A term of the type (1-x) in the denominator indicates the presence of a bosonic generator counted with fugacity x. We find a rich and universal set of such terms in the denominator showing an interesting bosonic Fock space in the spectrum of protected operators. This Fock space cannot be explained as coming from the non-interacting supersymmetric graviton gas far away from the black hole as in the grey-galaxy solutions because the charges of the bosonic generators are not compatible with those of the supersymmetric gravitons. This suggests a novel microstructure within the supersymmetric black hole itself. We also examine the indices of S-dual pairs SO(2N+1) and Sp(N) SYM. Although their full 1/16-BPS indices coincide, we find discrepancies in their BMN-sector indices. As the BMN indices restricted to the graviton sector are expected to be the same, this mismatch allows us to identify non-graviton cohomologies. We explicitly find one of them in the SO(7) theory that is responsible for the mismatch of the BMN index. We also show that indices restricted to other one-loop cohomology truncations, in general, do not match under S-duality. If the conjecture of exactness of one-loop cohomology is correct, this suggests the presence of new cohomology subrings that match under S-duality with the letter-based truncations of the one-loop cohomology. This offers a way to check the one-loop exactness conjecture.

hep-th↗

arXiv2025

Large charge operators at large spin from relativistically rotating vortices

We study the ground states of CFTs with a global $U(1)$ symmetry on $\mathbb{R}\times S^2$ in the regime of large charge $Q$ and large angular momentum $J$, using large charge EFT. We find that in the range $Q \ll J \ll Q^2$, the ground state solution is a superfluid densely populated with vortices rotating at a constant angular velocity $Ω$. This is a relativistic generalization of the known (non-relativistic) rigid rotation phase, which corresponds to the small $Ω$ limit of our solution. In the regime $Q^{3/2}\ll J\ll Q^2$, our solution achieves lower energy than previously identified states. In this regime, most of the vortices move near the speed of light, and we obtain the chiral fluctuation modes propagating at the speed of light. Interestingly, we find that our ground state can be interpreted as a zero temperature charged normal fluid rotating at a constant angular velocity $Ω$. We rederive this solution purely from the fluid dynamics. Based on the (already established) applicability of fluid description to large non-supersymmetric extremal AdS black holes, we find that the boundary stress tensor and $U(1)$ current of extremal AdS Kerr-Newman black hole align with those of our solution.

hep-th↗

arXiv2025

Dual Dressed Black Holes as the end point of the Charged Superradiant instability in ${\cal N} = 4$ Yang Mills

Charged Black holes in $AdS_5 \times S^5$ suffer from superradiant instabilities over a range of energies. Hairy black hole solutions (constructed within gauged supergravity) have previously been proposed as endpoints to this instability. We demonstrate that these hairy black holes are themselves unstable to the emission of large dual giant gravitons. We propose that the endpoint to this instability is given by Dual Dressed Black Holes (DDBH)s; configurations consisting of one, two, or three very large dual giant gravitons surrounding a core $AdS$ black hole with one, two, or three $SO(6)$ chemical potentials equal to unity. The dual giants each live at $AdS$ radial coordinates of order $\sqrt{N}$ and each carry charge of order $N^2$. The large separation makes DDBHs a very weakly interacting mix of their components and allows for a simple computation of their thermodynamics. We conjecture that DDBHs dominate the phase diagram of ${\cal N}=4$ Yang-Mills over a range of energies around the BPS plane, and provide an explicit construction of this phase diagram, briefly discussing the interplay with supersymmetry. We develop the quantum description of dual giants around black hole backgrounds and explicitly verify that DDBHs are stable to potential tunneling instabilities, precisely when the chemical potentials of the core black holes equal unity. We also construct the 10-dimensional DDBH bulk solutions.

hep-th↗

arXiv2025

Towards quantum black hole microstates

We study the cohomology of local BPS operators in $\mathcal{N}=4$ Yang-Mills theory. The finite $N$ cohomologies consist of the graviton part (subject to the stringy exclusion principle) and the rest which may describe black hole microstates in quantum AdS/CFT. We construct an infinite tower of non-graviton cohomologies in the $SU(2)$ theory and study to what extent they simulate quantum black holes. We find signals for partial no-hair behaviors by showing that certain gravitons are forbidden to dress these cohomologies. This is in qualitative agreement with the perturbative hairs allowed around black holes, which also leads us to a natural setup to construct hairy BPS black holes. The cohomologies are simpler to study in the BMN matrix model truncation of the classical field theory.

hep-th↗

arXiv2025

Exact QFT duals of AdS black holes

We construct large $N$ saddle points of the matrix model for the $\mathcal{N}=4$ Yang-Mills index dual to the BPS black holes in $AdS_5\times S^5$, in two different setups. When the two complex chemical potentials for the angular momenta are collinear, we find linear eigenvalue distributions which solve the large $N$ saddle point equation. When the chemical potentials are not collinear, we find novel solutions given by areal eigenvalue distributions after slightly reformulating the saddle point problem. We also construct a class of multi-cut saddle points, showing that they sometimes admit nontrivial filling fractions. As a byproduct, we find that the Bethe ansatz equation emerges from our saddle point equation.

hep-th↗

arXiv2024

The shape of non-graviton operators for $SU(2)$

The BPS spectrum of AdS/CFT exhibits multi-gravitons at low energies, while having black hole states at higher energies. This can be studied concretely in AdS$_5$/CFT$_4$ in terms of classical cohomologies, even in the quantum regimes at finite $1/N$. Recently, Chang and Lin found a threshold for non-graviton states in the $SU(2)$ maximal super-Yang-Mills theory. We explicitly construct and present this threshold cohomology.

hep-th↗

arXiv2024

Holographic Tests for Giant Graviton Expansion

It has been proposed that the superconformal index admits a novel reformulation, called giant graviton expansion. In this paper, we investigate the properties of dual $AdS_5$ black holes using the giant graviton expansion framework. First, we compute the entropy of black holes in $AdS_5\times S^5$ with fixed charges through a large $N$ saddle point analysis on the giant graviton index and further extremize it in the wrapping number. We identify a specific regime of fugacities where our saddle point analysis is valid. It turns out that this condition ensures the absence of closed-time-like curves and the stability of dual black hole solutions with equal charges. In addition, the giant graviton expansion of the index provides insights into how small black holes in AdS can be interpreted as bound states of branes. We extend our study to include the giant graviton expansion with the insertion of a half-BPS surface defect in $\mathcal{N}=4$ SYM with a $U(N)$ gauge group. Finally, we test the giant graviton expansion in various holographic theories whose dual geometries are $AdS_5\times S^5/\mathbb{Z}_k$ and $AdS_5\times SE_5$.

hep-th↗

arXiv2023

'Grey Galaxies' as an endpoint of the Kerr-AdS superradiant instability

Kerr-AdS$_{d+1}$ black holes for $d\geq 3$ suffer from classical superradiant instabilities over a range of masses above extremality. We conjecture that these instabilities settle down into Grey Galaxies (GGs) - a new class of coarse-grained solutions to Einstein's equations which we construct in $d=3$. Grey Galaxies are made up of a black hole with critical angular velocity $ω=1$ in the `centre' of $AdS$, surrounded by a large flat disk of thermal bulk gas that revolves around the centre of $AdS$ at the speed of light. The gas carries a finite fraction of the total energy, as its parametrically low energy density and large radius are inversely related. GGs exist at masses that extend all the way down to the unitarity bound. Their thermodynamics is that of a weakly interacting mix of Kerr-AdS black holes and the bulk gas. Their boundary stress tensor is the sum of a smooth `black hole' contribution and a peaked gas contribution that is delta function localized around the equator of the boundary sphere in the large $N$ limit. We also construct another class of solutions with the same charges; `Revolving Black Holes (RBHs)'. RBHs are macroscopically charged $SO(d,2)$ descendants of AdS-Kerr solutions, and consist of $ω=1$ black holes revolving around the centre of $AdS$ at a fixed radial location but in a quantum wave function in the angular directions. RBH solutions are marginally entropically subdominant to GG solutions and do not constitute the endpoint of the superradiant instability. Nonetheless, we argue that supersymmetric versions of these solutions have interesting implications for the spectrum of supersymmetric states in, e.g. ${\cal N}=4$ Yang-Mills theory.

hep-th↗

arXiv2022

From giant gravitons to black holes

We study AdS$_5$ black holes from a recently suggested giant graviton expansion formula for the index of $U(N)$ maximal super-Yang-Mills theory. We compute the large $N$ entropy at fixed charges and giant graviton numbers $n_I$ by a saddle point analysis, and further maximize it in $n_I$. This agrees with the dual black hole entropy in the small black hole limit. To get black holes at general sizes, one should note that various giant graviton indices cancel because gauge theory does not suffer from a Hagedorn-like pathology by an infinite baryonic tower. With one assumption on the mechanism of this cancellation, we account for the dual black hole entropy at general sizes. We interpret our results as analytic continuations of the large $N$ free energies of SCFTs, and based on it compute the entropies of AdS$_{4,7}$ black holes from M5, M2 giant gravitons.

hep-th↗

arXiv2021

Sign-tunable anomalous Hall effect induced by two-dimensional symmetry-protected nodal structures in ferromagnetic perovskite oxide thin films

Magnetism and spin-orbit coupling (SOC) are two quintessential ingredients underlying novel topological transport phenomena in itinerant ferromagnets. When spin-polarized bands support nodal points/lines with band degeneracy that can be lifted by SOC, the nodal structures become a source of Berry curvature; this leads to a large anomalous Hall effect (AHE). Contrary to three-dimensional systems that naturally host nodal points/lines, two-dimensional (2D) systems can possess stable nodal structures only when proper crystalline symmetry exists. Here we show that 2D spin-polarized band structures of perovskite oxides generally support symmetry-protected nodal lines and points that govern both the sign and the magnitude of the AHE. To demonstrate this, we performed angle-resolved photoemission studies of ultrathin films of SrRuO$_3$, a representative metallic ferromagnet with SOC. We show that the sign-changing AHE upon variation in the film thickness, magnetization, and chemical potential can be well explained by theoretical models. Our study is the first to directly characterize the topological band structure of 2D spin-polarized bands and the corresponding AHE, which could facilitate new switchable devices based on ferromagnetic ultrathin films.

cond-mat.str-el↗

arXiv2020

Fractional charge bound to a vortex in two dimensional topological crystalline insulators

We establish the correspondence between the fractional charge bound to a vortex in a textured lattice and the relevant bulk band topology in two-dimensional (2D) topological crystalline insulators. As a representative example, we consider the Kekule textured graphene whose bulk band topology is characterized by a 2D $\mathbb{Z}_{2}$ topological invariant $ν_{\rm 2D}$ protected by inversion symmetry. The fractional charge localized at a vortex in the Kekule texture is shown to be related to the change in the bulk topological invariant $ν_{\rm 2D}$ around the vortex, as in the case of the Su-Schriefer-Heeger model in which the fractional charge localized at a domain wall is related to the change in the bulk charge polarization between degenerate ground states. We show that the effective three-dimensional (3D) Hamiltonian, where the angle $θ$ around a vortex in Kekule-textured graphene is a third coordinate, describes a 3D axion insulator with a quantized magnetoelectric polarization. The spectral flow during the adiabatic variation of $θ$ corresponds to the chiral hinge modes of an axion insulator and determines the accumulated charge localized at the vortex, which is half-quantized when chiral symmetry exists. When chiral symmetry is absent, electric charge localized at the vortex is no longer quantized, but the vortex always carries a half-quantized Wannier charge as long as inversion symmetry exists. For the cases when magnetoelectric polarization is quantized due to the presence of symmetry that reverses the space-time orientation, we classify all possible topological crystalline insulators whose vortex defect carries a fractional charge.

cond-mat.mes-hall↗