arXiv subjects

Minkyu Lee

Publications and source records attributed to Minkyu Lee.

4 recordsLinked to original sources

arXiv2026

Comparing Self-Supervised and Domain-Invariant Features for Cross-Domain Voice Phishing Detection

Voice phishing detection faces three critical challenges: real criminal recordings are unavailable due to privacy constraints; when available, only a handful of samples exist, insufficient for fine-tuning; and lightweight acoustic-only detection is needed as an alternative to large self-supervised models. We compare domain-invariant prosodic features and self-supervised representations (HuBERT, wav2vec2.0) through cross-domain evaluation-training on scenario-based actor recordings and testing on authentic criminal calls. Domain-invariant prosodic features achieve 69.5% F1 zero-shot and 71.0% with 5-shot learning. HuBERT achieves highest performance (94.2% F1, 5-shot), while wav2vec2.0 exhibits a precision-oriented detection profile (90.2% F1 with 99.4% precision, 5-shot). These findings reveal fundamental trade-offs: domain-invariant features enable zero-shot deployment when no real data exists, while SSL methods achieve higher performance but require real samples and compute.

cs.SD↗

arXiv2026

Ground-State Energy Estimation of HeH$^{+}$, ArH$^{+}$, and H$_2$O via Sample-Based Quantum Diagonalization

Accurate ground-state energies are essential for understanding molecular structure, chemical bonding, and reaction energetics in quantum chemistry. In this work, we investigate the ground-state properties of the molecular systems HeH$^+$, ArH$^+$, and H$_2$O using Sample-Based Quantum Diagonalization (SQD), a hybrid quantum-classical framework designed for near-term quantum devices. Unlike variational approaches such as VQE, which require deep parameterized circuits and repeated expectation-value measurements, SQD reconstructs a low-energy determinant subspace directly from measured bitstrings. For the present calculations, bitstrings were generated on IBM quantum hardware using shallow local unitary cluster Jastrow (LUCJ) circuits whose parameters were constructed from the $t_1$ and $t_2$ amplitudes of coupled-cluster singles and doubles (CCSD) calculations based on restricted Hartree--Fock (RHF) references. From these samples, we compute ground-state potential-energy curves of HeH$^+$, ArH$^+$, and H$_2$O with the 6-31G and cc-pVDZ basis sets. For all three systems, the SQD results obtained with the cc-pVDZ basis closely follow the corresponding same-basis CCSD energies and reproduce the equilibrium-region trends of the potential-energy curves. HeH$^+$ and ArH$^+$ were chosen as simple yet astrophysically important molecular-ion benchmarks, while H$_2$O was included as a representative polyatomic molecule to assess the applicability of SQD beyond diatomic ionic systems. At the adopted equilibrium geometries, the deviations from the same-active-space CASCI references are 0.00, 2.51, and 6.34 mHa for HeH$^+$, ArH$^+$, and H$_2$O, respectively. These results demonstrate the feasibility of hardware-assisted SQD for the present benchmark systems and motivate further studies of its accuracy and computational scaling for larger molecular active spaces.

physics.chem-ph↗

arXiv2025

Empirical Reconstruction of the JSNS$^2$ KDAR $\nu_\mu$-$^{12}$C Missing-Energy Spectrum with a Two-Ex-Gaussian and Generalized-Tail Model

Recent analyses of the JSNS$^2$ monoenergetic $\nu_\mu$ scattering on $^{12}$C at 235.5~MeV have compared the measured missing-energy spectrum with several nuclear models, including \textsc{NuWro}, \textsc{GiBUU}, and RMF+Achilles. While these models reproduce the overall peak position, their respective $\chi^2$ values of $35.5$, $176.8$, and $58.1$ indicate that none can simultaneously describe the spectral width and the high-energy tail, reflecting limitations in the treatment of binding energy, two-particle--two-hole (2p-2h) excitations, and final-state interactions (FSI). To address these discrepancies, we introduce an empirical yet physically motivated representation of the spectrum based on two exponentially modified Gaussian (ex-Gaussian) components for p- and s-shell knockout and a generalized power-exponential continuum term describing multinucleon and FSI-induced strength. The fit reproduces the JSNS$^2$ data within the fitted energy range with $\chi^2=8.0$ for 6 degrees of freedom. yielding parameters that quantify asymmetric broadening of the s-shell while preserving a narrow quasielastic p-shell response. This compact model demonstrates that a minimal empirical framework can capture key features of the nuclear response and provides a useful reference for phenomenological comparisons and future studies of quasielastic and 2p-2h dynamics in the few-hundred-MeV regime.

hep-ph↗

arXiv2025

Precision Analysis of $\mathrm{^{12}C / ^{13}C}$ Ratios in Orion IRc2 Acetylene Isotopologues via $\chi^2$ Fitting

We present a detailed analysis of acetylene (C$_2$H$_2$) and its isotopologues in the Orion IRc2 region, focusing on the determination of $^{12}$C/$^{13}$C isotopic ratios using high-resolution infrared spectra from SOFIA. By employing a robust $\chi^2$ fitting method, we simultaneously determined temperature and column density, achieving a $^{12}$C/$^{13}$C ratio of $18.72^{+1.54}_{-1.46}$ for the blue clump and $15.07^{+1.61}_{-1.60}$ for the red clump. These results revealed significant discrepancies with the traditional rotational diagram method, which overestimated the ratios by 12.1% and 23.9%, respectively. Our $\chi^2$ approach also reduced uncertainties by up to 75%, providing more precise and reliable isotopic ratios. Additionally, we extended the analysis to isotopologues not covered in HITRAN, calculating vibrational and rotational constants through quantum chemical calculations. This allowed us to model subtle isotopic shifts induced by $^{13}$C and deuterium substitution, enabling accurate isotopologue detection in astrophysical environments. The Python package (TOPSEGI) developed in this study facilitates efficient $\chi^2$ fitting and isotopic ratio analysis, making it a valuable tool for future high-resolution observations. This work highlights the critical role of advanced spectral models and fitting techniques in understanding isotopic fractionation and the chemical evolution of interstellar matter.

astro-ph.GA↗