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Nuclear Theory·nucl-th

Tuesday·May 7, 2024

14 papers—10 primary·4 cross-listed

All14Primary10Cross-lists4
  1. 11

    [Submitted on 3 May 2024] (cross-list from hep-ph)

    Lepton-neutron interaction and S-wave low energy parameters

    Jaume Carbonell🇫🇷 · Tobias Frederico🇧🇷

    A lepton-neutron potential in configuration space is obtained. It is based on the Coulomb plus hyperfine interaction Hamiltonian integrated over the neutron charge and magnetic densities. Different parametrisations of the neutron electromagnetic form factors are compared. It is given in the operator form with a central, spin-spin, tensor and spin-orbit terms. The potentials for lowest partial waves states are presented. We compute the lepton-neutron lepton () low-energy parameters for the S-waves, estimate the zero-energy cross sections for higher angular momentum states, and point out a possible divergence in the partial wave summation due to the spin-orbit potential.

    Comments:
    16 pages, 10 figures, To appear in Phys. Rev. C
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); cond-mat.mtrl-sci (cond-mat.mtrl-sci); Nuclear Theory (nucl-th); Atomic Physics (physics.atom-ph); Quantum Physics (quant-ph)
    arXiv:
    2405.02407 [pdf]
    PRC(2024)·0 citations
  2. 12

    [Submitted on 4 May 2024] (cross-list from physics.chem-ph)

    Compactification of Determinant Expansions via Transcorrelation

    Abdallah Ammar · Anthony Scemama · Pierre-François Loos · Emmanuel Giner

    Although selected configuration interaction (SCI) algorithms can tackle much larger Hilbert spaces than the conventional full CI (FCI) method, the scaling of their computational cost with respect to the system size remains inherently exponential. Additionally, inaccuracies in describing the correlation hole at small interelectronic distances lead to the slow convergence of the electronic energy relative to the size of the one-electron basis set. To alleviate these effects, we show that the non-Hermitian, transcorrelated (TC) version of SCI significantly compactifies the determinant space, allowing to reach a given accuracy with a much smaller number of determinants. Furthermore, we note a significant acceleration in the convergence of the TC-SCI energy as the basis set size increases. The extent of this compression and the energy convergence rate are closely linked to the accuracy of the correlation factor used for the similarity transformation of the Coulombic Hamiltonian. Our systematic investigation of small molecular systems in increasingly large basis sets illustrates the magnitude of these effects.

    Comments:
    18 pages, 10 figures (supporting information available)
    Subjects:
    physics.chem-ph (physics.chem-ph); cond-mat.mtrl-sci (cond-mat.mtrl-sci); Strongly Correlated Electrons (cond-mat.str-el); Nuclear Theory (nucl-th)
    arXiv:
    2405.02640 [pdf]
    J.Chem.Phys.(2024)·3 citations
  3. 13

    [Submitted on 5 May 2024] (cross-list from cond-mat.quant-gas)

    Observation of Universal Expansion Anisotropy from Cold Atoms to Hot Quark-Gluon Plasma

    Ke Li🇨🇳 · Hong-Fang Song🇨🇳 · Hao-Jie Xu🇨🇳 · Yu-Liang Sun🇨🇳 · Fuqiang Wang🇨🇳

    Azimuthal anisotropy has been ubiquitously observed in high-energy proton-proton, proton-nucleus, and nucleus-nucleus (heavy-ion) collisions, shaking the early belief that those anisotropies require an intense phase of multiple interactions between the created particles. This work reports a study of anisotropic expansion of cold Li Fermi gases, initially trapped in an anisotropic potential, as a function of the interaction strength that can be readily tuned by an external magnetic field. It is found that the expansion anisotropy builds up quickly at small interaction strength, without the need of a large amount of interactions. An unexpected and quantitative universal scaling of the expansion anisotropy is observed for the first time between cold atom and heavy-ion systems as a function of the number of collisions per particle or opacity (), despite their vast differences in scale and physics. The expansion isotropy in both the cold atom gases and heavy-ion collisions increases smoothly and shows no sign of saturation in the observed opacity range, with an approximate power-law dependence of , characteristic of random walks. This universality potentially unifies a variety of vastly different physical systems, from weakly interacting dilute gases to the strongly interacting quark-gluon plasma of the early universe.

    Comments:
    29 pages, 12 figures; This manuscript has been accepted by Cell Press Newton
    Subjects:
    Quantum Gases (cond-mat.quant-gas); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2405.02847 [pdf]
    Newton 1 (2025) 100237·4 citations
  4. 14

    [Submitted on 6 May 2024] (cross-list from hep-ph)

    Generalized thermodynamic relations for perfect spin hydrodynamics

    Wojciech Florkowski🇵🇱 · Mykhailo Hontarenko🇵🇱

    Generalized thermodynamic relations are introduced into the framework of a relativistic perfect spin hydrodynamics. They allow for consistent treatment of spin degrees of freedom, including the use of spin tensors whose structure follows from microscopic calculations. The obtained results are important for establishing consistency between different formulations of spin hydrodynamics and form the basis for introducing dissipative corrections.

    Comments:
    significantly extended version including discussion of non-equilibrium corrections
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2405.03263 [pdf]
    PRL(2025)·30 citations

Affiliations

first authorsco-authorsvia INSPIRE