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Carnot's Entropy
Jean-louis Lénard
Posted: 21 September 2026
Analytical Closed-Form Reconstruction of Singular Shear-Strip Boundary Layers in Hypersonic Compressible Magnetohydrodynamic Continua and Explicit Verification Against Cosmological Event Horizons
Sami Mehennaoui
Posted: 21 September 2026
Pressure-Induced Enhancement of Superconductivity in 3R-TaSe2 Single Crystals
Jiahao Wang
,Wei Wu
,Shilin Zhu
,Yanmin Zhang
,Lei Qin
,Jianlin Luo
Posted: 20 September 2026
NFW Profiles as Fold Caustics: Fixed Core Regularization and the Case of IC2574
Swen C. Heinze
The Navarro–Frenk–White (NFW) profile occupies a central role in the description of dark-matter halos. Despite its remarkable empirical and numerical success, the physical origin of its universal inner scaling \[\rho(r)\propto r^{-1}\] remains a subject of ongoing discussion, particularly in connection with the longstanding cusp–core problem. This paper explores the possibility that the inner NFW cusp may admit a geometric interpretation. Motivated by the universal structure of fold caustics in singularity theory, we investigate whether the characteristic inner NFW scaling can be understood as the radial manifestation of a projected fold singularity rather than solely as a consequence of collisionless halo dynamics. A central observation motivates the present work. Ideal fold caustics are singular only in idealized mathematical limits in which finite physical scales are removed. Across wave optics, gravitational lensing, collisionless phase-space dynamics, and other physical systems, the observed realization of a caustic is generically regularized by finite intrinsic scales. The observed finite structure is not the exception. The singularity is. This suggests a different perspective on the cusp–core problem. If the NFW cusp represents the ideal mathematical form of an underlying fold-like structure, then the observed finite core may not require a separate explanation. Instead, the core may represent the physically expected realization of that structure, while the perfectly unregularized cusp corresponds to an idealized limiting case. To explore this possibility, we consider a simple fixed-width regularization of the NFW cusp, \(\rho(r)=\frac{\rho_s}{(r/r_s+\epsilon)(1+r/r_s)^2},\) with a representative dimensionless regularization scale of order \(\epsilon\sim0.1\). As a proof-of-concept example, the dwarf galaxy IC2574 is used to test whether such a fixed regularization can reproduce an observed core-dominated system while preserving the characteristic outer behavior of the NFW profile. The purpose of the present work is not to challenge the cosmological success of \(\Lambda\)CDM, modify gravity, or introduce a new dark-matter model. Rather, it investigates whether the universal NFW cusp may admit a complementary geometric interpretation as a fold-caustic structure and whether the observed galactic cores may naturally arise as the physical regularization of that structure.
The Navarro–Frenk–White (NFW) profile occupies a central role in the description of dark-matter halos. Despite its remarkable empirical and numerical success, the physical origin of its universal inner scaling \[\rho(r)\propto r^{-1}\] remains a subject of ongoing discussion, particularly in connection with the longstanding cusp–core problem. This paper explores the possibility that the inner NFW cusp may admit a geometric interpretation. Motivated by the universal structure of fold caustics in singularity theory, we investigate whether the characteristic inner NFW scaling can be understood as the radial manifestation of a projected fold singularity rather than solely as a consequence of collisionless halo dynamics. A central observation motivates the present work. Ideal fold caustics are singular only in idealized mathematical limits in which finite physical scales are removed. Across wave optics, gravitational lensing, collisionless phase-space dynamics, and other physical systems, the observed realization of a caustic is generically regularized by finite intrinsic scales. The observed finite structure is not the exception. The singularity is. This suggests a different perspective on the cusp–core problem. If the NFW cusp represents the ideal mathematical form of an underlying fold-like structure, then the observed finite core may not require a separate explanation. Instead, the core may represent the physically expected realization of that structure, while the perfectly unregularized cusp corresponds to an idealized limiting case. To explore this possibility, we consider a simple fixed-width regularization of the NFW cusp, \(\rho(r)=\frac{\rho_s}{(r/r_s+\epsilon)(1+r/r_s)^2},\) with a representative dimensionless regularization scale of order \(\epsilon\sim0.1\). As a proof-of-concept example, the dwarf galaxy IC2574 is used to test whether such a fixed regularization can reproduce an observed core-dominated system while preserving the characteristic outer behavior of the NFW profile. The purpose of the present work is not to challenge the cosmological success of \(\Lambda\)CDM, modify gravity, or introduce a new dark-matter model. Rather, it investigates whether the universal NFW cusp may admit a complementary geometric interpretation as a fold-caustic structure and whether the observed galactic cores may naturally arise as the physical regularization of that structure.
Posted: 20 September 2026
Quantum Anomalous Hall Transport in Physical–Observation Dual-Axis Geometry: Mixed Chern Curvature, Fixed-Source Recovery, and a Quantized Observation Cycle
Xianwei Meng
Posted: 20 September 2026
Derivation of Time, Velocity, Mass, and Gravity from Planck Units
Amrit Šorli
Posted: 20 September 2026
TF-RSE-IonCF v3.1: A Unified Closed-Form Model for the Total Electron Binding Energy of All Neutral Atoms and Ions (Z = 1–92, q = 0 to Z–1)
Jinjun Cheng
,Dian Cheng
Posted: 20 September 2026
Mercury’s Perihelion Precession in a Unified Description of Gravity and Motion: A Hamiltonian Approach
Javier Galán
Posted: 20 September 2026
Diastolic Pressure and Heart Rate-Dependent Modulation of Arterial Wave Reflection in a Biophysical Cardiovascular Model
Ljubica Ilić
,Isidora Janićijević-Grubišić
,Aleksandra Markoski Smiljković
,Svetislav Pelemiš
,Marko Pajić
,Biljana Smiljković
,Katarina Žikić
,Dejan Žikić
Posted: 20 September 2026
The Lucron Model: A Single-Scale Ontology for Space, Matter, Gravity, and Quantum Mechanics
Guillermo Antonio Cabello Rivas
Posted: 18 September 2026
Selecting Microscopic Degrees of Freedom for Emergent Spacetime:
Coupled Quantum Oscillators as the Substrate
Harry Tong
Posted: 18 September 2026
Limits of Scalar Descriptors in Chiral Magnet Screening
Aleksei Novgorodtsev
Posted: 18 September 2026
Transitional Layer at the Edge of a False Vacuum in a Cavitation Model of the Big Bang
Mikhail Pekker
,Mikhail N. Shneider
Posted: 18 September 2026
Exact Navier–Stokes Solutions for Strained Shear Layers on a Stretching Sheet
Bo Hua Sun
Posted: 18 September 2026
Stress-Gated Ion Transport Controls Lithium Filament Propagation in Solid Electrolytes: A Second, Exponential Channel of Chemo-Mechanical Coupling
Bo Hua Sun
Posted: 18 September 2026
Regime-Dependent Effectiveness of Spectral Nudging in WRF-Chem: Meteorological and Saharan Dust Skill over the Central Mediterranean
Alessandra Chiappini
,Umberto Rizza
,Giorgio Passerini
,Antonio Ricchi
Posted: 18 September 2026
The Phase Transport Fundamental Equation on the Physical–Observation Dual-Axis Structure
Xianwei Meng
Posted: 18 September 2026
Multiplicative Decomposition-Embedded Logarithmic Strain-Based Statements for Viscoelasticity in Glaciological Applications
Paul Namalomba
,Sebastian Skatulla
,Carlo Sansour
,Maxime Nutte
,Michael Kaliske
Posted: 18 September 2026
A Fast Operator-Interpolation Mapped Spectral Method for Variable-Order Fractional PDEs
Carlo Cattani
,Yusif Gasimov
Posted: 18 September 2026
The Spiral Structure Model: A Geometric Phenomenology of Wave-Particle Duality, Spin, and Electromagnetic Coupling
Jinjun Cheng
,Dian Cheng
Posted: 18 September 2026
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