Nuclear Theory·nucl-th

Wednesday·January 14, 2026

10 papers—5 primary·5 cross-listed

01
Merging multidimensional equations of state of strongly interacting matter via a statistical mixture
Yumu Yang🇺🇸 · Prachi Garella🇺🇸 · Musa R. Khan🇺🇸 · Tulio E. Restrepo🇺🇸 · Joaquin Grefa🇺🇸 · Johannes Jahan🇺🇸 · Mauricio Hippert🇧🇷 · Jorge Noronha🇺🇸 · Claudia Ratti🇺🇸 · Romulo Rougemont🇧🇷
We introduce a general method to merge multidimensional equations of state (EoSs) by combining them in a two-fluid equilibrium statistical mixture in the grand canonical ensemble. The merged grand potential density $ω$ is built directly from the input EoSs and the fluid fractions are fixed by minimizing $ω$ at fixed temperature $T$ and baryon chemical potential $μ_{B}$ . Thermodynamic consistency and stability are guaranteed as all thermodynamic quantities are consistently derived from a single merged grand potential $ω (T, μ_{B})$ with the correct convexity properties. Our method can accommodate a first-order phase transition and a critical endpoint with mean-field critical exponents. We use this method to merge a van der Waals Hadron-Resonance-Gas EoS with a holographic Einstein-Maxwell-Dilaton EoS that has a critical point and a first-order line. The result is a single EoS, spanning hadronic and deconfined matter over a broad range in $(T, μ_{B})$ , which can be readily used in heavy-ion hydrodynamic simulations. Our merging method can be generalized to consider a higher dimensional phase diagram (e.g., by considering more chemical potentials) and more than two input EoSs.
nucl-thhep-lathep-phPRD(2026)·9 citations
02
Light Nuclei embedded in a Nuclear Medium: Clustering and Mott Transitions
Qi Meng🇨🇳 · Chang Xu🇨🇳
The clustering of nucleons is a fundamental phenomenon with broad implications for nuclear physics and astrophysics. In this work, we employ a microscopic in-medium few-body approach to systematically investigate the formation and dissolution of light clusters (deuteron, $^{3} H$ , $^{3} He$ , $α$ -particle) embedded in nuclear medium. The medium-modified cluster structures under the Pauli blocking and the picture of Mott transitions in nuclear medium are discussed in detail. We find that the weakly bound deuteron survives to higher densities as compared with the more compact $α$ -particle in symmetric nuclear matter, with its r.m.s. radius expanding markedly prior to its dissolution. Moreover, the Mott density of $α$ -particle is slightly lower in neutron-rich matter than in symmetric matter. These results may provide useful constraints for the formation of light clusters at nuclear surface and the cluster yields in intermediate-energy heavy-ion collisions.
nucl-thnucl-exPRC(2026)·2 citations
03
Chiral three-nucleon forces for the new local position-space two-nucleon potential in $ab initio$ many-body calculations
Rongzhe Hu🇨🇳 · Jianguo Li🇨🇳 · Siqin Fan🇨🇳 · Furong Xu🇨🇳
Three-nucleon force (3NF) plays an important role in understanding the structure of finite nuclei and the saturation properties of infinite nuclear matter. More specifically, 3NF should be necessary for each two-nucleon force (2NF) to obtain more accurate description of nuclear systems. 3NF derived from the chiral effective field theory has been successful in $ab initio$ calculations of atomic nuclei. Most of established chiral nuclear forces have a nonlocal form in the momentum space. In this work, we construct a companion chiral 3NF specifically tailored to the new Idaho local position-space 2NF, and calculate binding energies and radii of nuclei up to $^{132}$ Sn. We find that a chiral 3NF with hybrid local and nonlocal regulators has advantages in improving the nuclear structure calculations of both binding energies and radii with the new Idaho 2NF. The two low-energy constants of 3NF are constrained by the ground-state energies of $^{3}$ H and $^{16}$ O as suggested in a recent work.
nucl-thastro-ph.HEnucl-exPRC(2026)·2 citations
04
Coherent Absorption Dynamics: The Dual Role of Off-Diagonal Couplings in Weakly Bound Nuclei
Hao Liu · Jin Lei · Zhongzhou Ren
Disentangling reaction mechanisms in weakly bound nuclei remains a long-standing challenge, complicated by the common practice of treating absorption as an incoherent sum of channel contributions. Within the continuum-discretized coupled-channels (CDCC) framework, we apply the generalized optical theorem [Nucl. Phys. A 842, 48 (2010)] and show that the total absorption cross section, $σ_{A} \propto - ⟨ Ψ∣ W ∣Ψ ⟩$ , decomposes as $σ_{A} = σ_{D} + σ_{B} + σ_{in t}$ , where $σ_{in t}$ is a coherent interference term between channel components. For the systems and complex fragment-target optical potentials considered, $σ_{in t}$ is negative and comparable in magnitude to the direct absorption terms. The off-diagonal imaginary couplings play a dual role: they redistribute flux among channels and generate $σ_{in t}$ , which is required for flux-balance consistency. In calculations for $d +^{93}$ Nb and $^{6}$ Li $+^{59}$ Co/ $^{208}$ Pb, retaining the full non-diagonal coupling matrix nearly doubles the breakup-channel absorption for the heavy target, while reducing the total absorption through $σ_{in t}$ . Neglecting the off-diagonal imaginary couplings $W_{ij}$ ( $i \neq = j$ ) is not merely an approximation but leads to a systematically biased physical picture: the total absorption is overestimated while the breakup absorption component is severely underestimated. Experimental analyses that employ incoherent-sum models to extract direct and breakup cross sections from data will inherit this bias. The full coupling matrix is therefore essential for mechanism-resolved cross-section extraction, and we advocate that experimentalists adopt full-coupling CDCC calculations as the standard for consistent interpretation of absorption data in weakly bound systems.
nucl-thPRC(2026)·5 citations
05
Dipole response in deformed halo nuclei $^{42} Mg$ and $^{44} Mg$
X. F. Jiang · Z. Z. Li · X. W. Sun · J. Meng
The quasiparticle finite amplitude method based on the deformed relativistic Hartree-Bogoliubov theory in continuum has been developed for the noncharge-exchange multipole response. Taking neutron-rich magnesium isotopes as examples, the isovector electric dipole response, especially in the low-lying region, is studied. It is found that the low-energy dipole strength increases with neutron number and becomes notably enhanced in the predicted deformed halo nuclei $^{42} Mg$ and $^{44} Mg$ . In these isotopes, the $K^{π} = 1^{-}$ states below 3 MeV are dominated by transitions from the ``halo" part of the single-neutron orbitals. Their transition densities reveal a low-frequency, out-of-phase oscillation between the neutron halo and the core. These results provide a microscopic picture for the soft dipole resonance in $^{42} Mg$ and $^{44} Mg$ .
nucl-thPLB(2026)·1 citation
06
Graphene is neither Relativistic nor Non-Relativistic case: Thermodynamics Aspects
Thandar Zaw Win · Cho Win Aung · Gaurav Khandal · Sabyasachi Ghosh
Discovery of electron hydrodynamics in graphene system has opened a new scope of analytic calculations in condensed matter physics, which was traditionally well cultivated in science and engineering as a non-relativistic hydrodynamics and in high energy nuclear and astro physics as relativistic hydrodynamics. Electrons in graphene follow neither non-relativistic nor relativistic hydrodynamics and thermodynamics. Present article has gone through systematic microscopic calculations of thermodynamical quantities like pressure, energy density, etc. of electron-fluid in graphene and compared with corresponding estimations for non-relativistic and ultra-relativistic cases. Identifying the Dirac fluid and Fermi liquid domains, we have sketched the transition of temperature and Fermi energy dependency of electron thermodynamics for graphene and other cases. An equivalent transition for quark matter is also discussed. The most exciting part is the general expression of specific heat, whose Fermi to Dirac fluid domain transition can be realized as a transition from a solid-based to a fluid-based picture. This understanding may be connected to the experimentally observed Wiedemann-Franz Law violation in the Dirac fluid domain of graphene system.
↳ cond-mat.str-elcond-mat.mes-hallcond-mat.stat-mechnucl-thPramana (2025)·4 citations
07
General gravitational properties of neutron stars: curvature invariants, binding energy, and trace anomaly
Iván Garibay🇩🇪 · Christian Ecker🇩🇪 · Luciano Rezzolla🇩🇪
We investigate the behavior of curvature invariants for a large ensemble of neutron stars built with equations of state (EOSs) that satisfy constraints from nuclear theory and perturbative QCD, as well as measurements of neutron-star masses, radii, and gravitational waves from binary neutron-star mergers. Surprisingly, our analysis reveals that stars with negative Ricci scalar $R$ are rather common and about $\sim 50%$ of our EOSs produce one or more stars with Ricci curvature that is negative somewhere inside the star. The negative curvature is found mostly but not exclusively at the highest densities and pressures, and predominantly for stiff EOSs and for the most compact and most massive stars. Furthermore, we improve the quasi-universal relation between the stellar gravitational mass $M$ and the baryonic mass $M_{b}$ , which allows us to express analytically one in terms of the other with a maximum variance of only $\sim 3%$ . Finally, using the relation between the Ricci scalar and the trace anomaly $Δ$ , we determine the conditions under which $Δ$ vanishes or becomes negative in neutron stars.
↳ gr-qcastro-ph.HEnucl-thPRD(2026)·4 citations
08
Insights into Meson and Baryon Structure using Continuum Schwinger Function Methods
Daniele Binosi🇮🇹 · Craig D. Roberts🇨🇳 · Zhao-Qian Yao🇩🇪
The bulk of visible mass is supposed to emerge from nonperturbative dynamics within quantum chromodynamics (QCD). Following years of development and refinement, continuum and lattice Schwinger function methods have recently joined in revealing the three pillars that support this emergent hadron mass (EHM); namely, a nonzero gluon mass-scale, a process-independent effective charge, and dressed-quarks with running masses that take constituent-like values at infrared momenta. One may argue that EHM and confinement are inextricably linked; and theory is now working to expose their manifold expressions in hadron observables and highlight the types of measurements that can be made in order to validate the paradigm. This contribution sketches these ideas via the unified explanation of pion and proton electromagnetic and gravitational form factors.
↳ hep-phhep-exhep-latnucl-ex+1J.Subatomic Part.Cosmol.(2026)·1 citation
09
Lattice-based equation of state with a critical point from constant entropy contours and its comparison to effective QCD approaches
Hitansh Shah🇺🇸 · Mauricio Hippert🇧🇷 · Jorge Noronha🇺🇸 · Claudia Ratti🇺🇸 · Volodymyr Vovchenko🇺🇸
In this work, we systematically assess the performance of a new method from [H. Shah et al., Phys. Rev. C 113, L012201] for locating the QCD critical point using constant-entropy contours by testing it against various effective QCD approaches. We demonstrate that, while the method yields spurious critical points in purely hadronic models (HRG) due to non-parabolic contour behavior at low temperatures ( $T ≲ 120$ MeV), it accurately reproduces the CP location in frameworks that feature a genuine phase transition and benchmarked against lattice QCD, such as Holographic Einstein-Maxwell-Dilaton, and Functional QCD approaches. Building on our previous determination of constant entropy contours using lattice data, we extend that analysis to construct a complete Lattice-based Equation of State (EoS) at finite density, which features a critical point at $(T, μ_{B}) \approx (114, 602)$ MeV. By integrating the extrapolated entropy density with respect to temperature, we reconstruct the pressure, baryon density, susceptibility, and speed of sound in the critical region, and analyze the focusing behavior of isentropic trajectories in the vicinity of the critical point.
↳ hep-phnucl-thPRD(2026)·3 citations
10
The Quantum Complexity of String Breaking in the Schwinger Model
Sebastian Grieninger🇺🇸 · Martin J. Savage🇺🇸 · Nikita A. Zemlevskiy🇺🇸
String breaking, the process by which flux tubes fragment into hadronic states, is a hallmark of confinement in strongly-interacting quantum field theories. A suite of quantum complexity measures is examined using Matrix Product States to characterize the string breaking process in the 1+1D Schwinger model. We demonstrate the presence of nonlocal quantum correlations along the string that may affect fragmentation dynamics, and show that entanglement and magic offer complementary perspectives on string formation and breaking beyond conventional observables.
↳ hep-phhep-lathep-thnucl-th+119 citations

Affiliations

first authorsco-authorsvia INSPIRE