Nuclear Theory·nucl-th

Wednesday·October 8, 2025

6 papers—6 primary·0 cross-listed

01
Ab initio study of the neutron and Fermi polarons on the lattice
Ryan Curry🇨🇦 · Jasmine Kozar🇨🇦 · Alexandros Gezerlis🇨🇦
We have used the auxiliary-field quantum Monte Carlo (AFQMC) many-body approach on the lattice to study the equation of state for a fermionic impurity interacting with a background sea of spin-polarized fermions. The impurity, or polaron, is an interesting system in both cold atomic and nuclear physics. Our approach is general, and we are able to straightforwardly study the polaron across these regimes. We first study the Fermi polaron at unitarity and for a wide range of scattering lengths, comparing against previous theoretical and experimental studies. We then explore the neutron polaron which has been shown to be an important constraint for nuclear physics. We have also employed the recently developed parametric matrix model to emulate AFQMC solutions to the two-body problem on the lattice, to accelerate the tuning of our lattice Hamiltonian parameters directly to two-body energies in a periodic box, following Luscher's formula. Our lattice quantum Monte Carlo results for the polaron in both a cold atomic and nuclear physics context can serve as stringent benchmarks for future theoretical and experimental research.
nucl-thcond-mat.quant-gasPRC(2026)·4 citations
02
Beyond $ρ^{2/3}$ Scaling: Microscopic Origins and Multimessengers of High-Density Nuclear Symmetry Energy
Bao-An Li🇺🇸
Nuclear symmetry energy $E_{sym} (ρ)$ encoding the cost to make nuclear matter more neutron rich has been the most uncertain component of the EOS of dense neutron-rich nucleonic matter. It affects significantly the radii, tidal deformations, cooling rates and frequencies of various oscillation modes of isolated neutron stars as well as the strain amplitude and frequencies of gravitational waves from their mergers, besides its many effects on structures of nuclei as well as the dynamics and observables of their collisions. Siemens (1970s) observed that $E_{sym} (ρ)$ scales as $(ρ / ρ_{0})^{2/3}$ near the saturation density $ρ_{0}$ of nuclear matter, since both the kinetic part and the potential contribution (quadratic in momentum) exhibit this dependence. The scaling holds if: (1) the nucleon isoscalar potential is quadratic in momentum, and (2) the isovector interaction is weakly density dependent. After examining many empirical evidences and understanding theoretical findings in the literature we conclude that: (1) Siemens' $ρ^{2/3}$ scaling is robust and serves as a valuable benchmark for both nuclear theories and experiments up to $2 ρ_{0}$ but breaks down at higher densities, (2) Experimental and theoretical findings about $E_{sym} (ρ)$ up to $2 ρ_{0}$ are broadly consistent, but uncertainties remain large for its curvature $K_{sym}$ and higher-order parameters, (3) Above $2 ρ_{0}$ , uncertainties grow due to poorly constrained spin-isospin dependent tensor and three-body forces as well as the resulting nucleon short-range correlations. Looking forward, combining multimessengers from both observations of neutron stars and terrestrial heavy-ion reaction experiments is the most promising path to finally constraining precisely the high-density $E_{sym} (ρ)$ and the EOS of supradense neutron-rich matter.
nucl-thastro-ph.HEhep-phhep-th+1Eur. Phys. J. Spec. Top. (2026)·10 citations
03
Factorial cumulants of proton multiplicity near a critical point using maximum entropy freeze-out prescription
Jamie Karthein🇺🇸 · Maneesha Pradeep🇺🇸 · Krishna Rajagopal🇺🇸 · Mikhail Stephanov🇺🇸 · Yi Yin🇨🇳
We present the first application of the maximum-entropy freeze-out prescription to calculate factorial cumulants of proton multiplicities near the conjectured QCD critical point in thermal equilibrium. We map the Gibbs free energy of the 3D Ising model to a parameterized class of possible EoS near QCD critical point. This equilibrium baseline highlights how factorial cumulants isolate critical fluctuations by subtracting trivial self-correlations, setting the stage for future out-of-equilibrium analyses. We identify the key non-universal aspects of the mapping to the Ising model that strongly control the characteristic properties, such as magnitude and location of the peaks of the factorial cumulants along the freeze-out curve.
nucl-thEPJ Web Conf.(2026)·1 citation
04
Microscopic study of nuclei synthesis in pycnonuclear reaction $^{12}$ C + $^{12}$ C in neutron stars
S.P. Maydanyuk (1 and 2) · Ju-Jun Xie (1, 3 and 4) · V.S. Vasilevsky (5) · K.A. Shaulskyi (2) ((1) Southern Center for Nuclear-Science Theory (SCNT), Institute of Modern Physics, Chinese Academy of Sciences, Huizhou 516000, China, (2) Institute for Nuclear Research, National Academy of Sciences of Ukraine, Kyiv, 03680, Ukraine, (3) Heavy Ion Science and Technology Key Laboratory, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China, (4) School of Nuclear Sciences and Technology, University of Chinese Academy of Sciences, Beijing 101408, China, (5) Bogolyubov Institute for Theoretical Physics, Metrolohichna str., 14b, Kyiv, 03143, Ukraine)
Purpose To investigate synthesis of nuclei in pycnonuclear reactions in dense medium of neutron stars on the basis of understanding, how the compound nucleus is formed during collision of two nuclei. To implement microscopic formulation of nuclear interactions and fusion in pycnonuclear reactions in dense medium. Methods (1) Nuclei synthesis in pycnonuclear reaction in dense medium of neutron star is investigated in the folding approximation of the cluster model. (2) Formation of compound nucleus in dense medium is studied with the method of Multiple Internal Reflections. Results (1) Wave functions of resonance states of $^{24}$ Mg are determined by interaction of two $^{12}$ C nuclei. (2) Clear maxima of probability of formation of compound nucleus in dense stellar medium are established at first time. (3) Difference between quasibound energies for potential of Woods-Saxon type and folding potentials with the shell-model approximation for wave functions is essential. (4) Formation of the compound nucleus is much more probable in the quasibound states than in states of zero-point vibrations. (5) Only the first quasibound energies for $^{12}$ C + $^{12}$ Care smaller than the barrier maximums. At these energies compound nuclear system has barrier which prevents its decay going through tunneling phenomenon. This is the new excited nucleus $^{24}$ Mg synthesised in the neutron star. \item[Conclusions] Cluster approach with folding potential provides significant modification of picture of formation of compound nucleus, previously obtained concerning the potential of Woods-Saxon type. The highest precision is provided by the folding potential, created by semi-realistic nucleon-nucleon potential and shell-model description of the internal structure of interacting $p$ -shell nuclei.
nucl-thastro-ph.SRhep-thnucl-exPhysics Letters B, 140191, (2026), ISSN 0…·0 citations
05
Fragmentation patterns of nuclear response: low-spin giant resonances and soft modes
Elena Litvinova🇺🇸
Nuclear resonances provide a rich and versatile testbed for exploring fundamental aspects of physics, particularly within the domain of strongly correlated many-body systems. The overarching goal of the theory is to develop a consistent and predictive framework that is (i) capable of a spectroscopically accurate description and (ii) sufficiently general to be applied across different energy scales and transferable to a wide range of complex systems. Thoroughly capturing emergent collective phenomena that arise in nuclear media is the central challenge for the theory, which is discussed in this contribution. It concentrates on the themes inspired and influenced by Angela Bracco's research, in particular, on the fragmentation patterns of the monopole and dipole responses of medium-heavy nuclei and associated open problems.
nucl-thEPJA(2025)·2 citations
06
Low lying isomers in the region of superheavy nuclei
Fritz Peter Hessberger🇩🇪
In the present study we want to give an overview on low lying isomeric states in the heaviest nuclei. After a short report on the early history on the discovery of nuclear isomerism and attempts to understand their physical nature, decay probabilities and structure of all low lying isomeric states in heaviest nuclei with half-lives typically longer than one microsecond are presentet. Special emphasisis is laid on cases where the above mentioned properties are still unclear or under discussion. We do not claim to have solved the problems in that cases, we rather want to give som hints for further discussions.
nucl-th1 citation

Affiliations

first authorsco-authorsvia INSPIRE

Ab initio study of the neutron and Fermi polarons on the lattice

Beyond ρ2/3 Scaling: Microscopic Origins and Multimessengers of High-Density Nuclear Symmetry Energy

Factorial cumulants of proton multiplicity near a critical point using maximum entropy freeze-out prescription

Microscopic study of nuclei synthesis in pycnonuclear reaction 12C + 12C in neutron stars

Fragmentation patterns of nuclear response: low-spin giant resonances and soft modes

Low lying isomers in the region of superheavy nuclei

Affiliations

Beyond $ρ^{2/3}$ Scaling: Microscopic Origins and Multimessengers of High-Density Nuclear Symmetry Energy

Microscopic study of nuclei synthesis in pycnonuclear reaction $^{12}$ C + $^{12}$ C in neutron stars