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Nuclear Theory·nucl-th

Monday·May 15, 2023

9 papers—3 primary·6 cross-listed

All9Primary3Cross-lists6
  1. 04

    [Submitted on 11 May 2023] (cross-list from hep-ph)

    On the role of isospin violation in the pion-nucleon -term

    Martin Hoferichter🇨🇭 · Jacobo Ruiz de Elvira🇪🇸 · Bastian Kubis🇩🇪 · Ulf-G. Meißner🇩🇪

    In recent years, a persistent tension between phenomenological and lattice QCD determinations of the pion-nucleon -term has developed. In particular, lattice-QCD calculations have matured to the point that isospin-violating effects need to be included. Here, we point out that the standard conventions adopted in both fields are incompatible, with the data-driven extraction based on the charged-pion mass, but lattice-QCD conventions relying on the mass of the neutral pion to define the isospin limit. The corresponding correction amounts to when evaluated in chiral perturbation theory with low-energy constants determined from a Roy-Steiner analysis of pion-nucleon scattering as well as itself. It reduces the tension with lattice QCD, and should be included in the comparison to phenomenological determinations. We also update the extraction from pionic atoms accounting for the latest measurement of the width of pionic hydrogen, , and provide the corresponding set of scalar couplings of the nucleon.

    Comments:
    6 pages, 1 figure; journal version
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
    arXiv:
    2305.07045 [pdf]
    PLB(2023)·43 citations
  2. 05

    [Submitted on 11 May 2023] (cross-list from hep-ph)

    Neutrino oscillations in the interaction picture

    Massimo Blasone🇮🇹 · Francesco Giacosa🇵🇱 · Luca Smaldone🇵🇱 · Giorgio Torrieri🇵🇱

    We study the mixing of different kind of fields (scalar in 0+1D, scalar in 3+1D, fermion in 3+1D) treating the mixing term as an interaction. To this aim, we employ the usual perturbative series in the interaction picture. We find that expression for flavor changing probability exhibits corrections with respect to the usual quantum mechanical (e.g. neutrino) oscillation formula, in agreement with the result previously obtained in the non-perturbative flavor Fock space approach.

    Comments:
    Accepted for publication in EPJC
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2305.07107 [pdf]
    EPJC(2023)·15 citations
  3. 06

    [Submitted on 11 May 2023] (cross-list from hep-th)

    Entanglement in a holographic Schwinger pair with confinement

    Sebastian Grieninger🇺🇸 · Dmitri E. Kharzeev🇺🇸 · Ismail Zahed🇺🇸

    We revisit the entanglement of a Schwinger pair created by external fields of arbitrary strength, using a holographic dual description of QCD. When external fields are strong in comparison to the string tension, the entanglement is geometrically tied to the Einstein-Rosen (ER) bridge in the bulk, and disappears when the pair production is not exponentially suppressed at the boundary. For moderate external fields, the entanglement is shown to follow from the geometrical interplay between the position of the ER bridge and the confining wall in the bulk. We clarify the physical nature of quantum entanglement in pair production, and connect it to the entropy of entanglement between the left- and right-moving fermions. In particular, we clarify the effect of real radiation off the produced particles on quantum entanglement of the pair.

    Comments:
    11 pages, 6 figures
    Subjects:
    High Energy Physics — Theory (hep-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2305.07121 [pdf]
    PRD(2023)·23 citations
  4. 07

    [Submitted on 12 May 2023] (cross-list from hep-ph)

    Quark matter under strong electric fields in the Linear Sigma Model coupled with quarks

    William R. Tavares🇧🇷 · Sidney S. Avancini🇧🇷 · Ricardo L. S. Farias🇧🇷

    In this work we study the influence of external electric field and temperature on the chiral phase transition of Quantum Chromodynamics. We use the two-flavor Linear Sigma Model coupled with quarks (LSMq) in a thermal and electrized medium to evaluate the effective quark mass and the Schwinger pair production. To this end, we apply one-loop correction to the fermionic sector of the model and the simple tree-level approximation in the mesonic contributions. The electric fields strengthen the partial restoration of the chiral symmetry when applied with finite temperature in a crossover transition. The expected decrease of the pseudocritical temperature as a function of the electric field is observed until electric fields reach . For stronger electric fields, the effect is the opposite, which is in a very good agreement with previous results obtained with four-point non-renormalizable models, showing that this effect is independent of renormalizability issues. We also show the thermal and electric effects on the behavior of the Schwinger pair production.

    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
    arXiv:
    2305.07188 [pdf]
    PRD(2023)·8 citations
  5. 08

    [Submitted on 12 May 2023] (cross-list from quant-ph)

    Message-Passing Neural Quantum States for the Homogeneous Electron Gas

    Gabriel Pescia · Jannes Nys · Jane Kim · Alessandro Lovato · Giuseppe Carleo

    We introduce a message-passing-neural-network-based wave function Ansatz to simulate extended, strongly interacting fermions in continuous space. Symmetry constraints, such as continuous translation symmetries, can be readily embedded in the model. We demonstrate its accuracy by simulating the ground state of the homogeneous electron gas in three spatial dimensions at different densities and system sizes. With orders of magnitude fewer parameters than state-of-the-art neural-network wave functions, we demonstrate better or comparable ground-state energies. Reducing the parameter complexity allows scaling to electrons, previously inaccessible to neural-network wave functions in continuous space, enabling future work on finite-size extrapolations to the thermodynamic limit. We also show the Ansatz's capability of quantitatively representing different phases of matter.

    Comments:
    13 pages, 5 figures
    Subjects:
    Quantum Physics (quant-ph); Strongly Correlated Electrons (cond-mat.str-el); Nuclear Theory (nucl-th); Computational Physics (physics.comp-ph)
    arXiv:
    2305.07240 [pdf]
    PRB(2024)·56 citations
  6. 09

    [Submitted on 12 May 2023] (cross-list from astro-ph.HE)

    Phase Transition Phenomenology with Nonparametric Representations of the Neutron Star Equation of State

    Reed Essick🇨🇦 · Isaac Legred🇺🇸 · Katerina Chatziioannou🇺🇸 · Sophia Han🇨🇳 · Philippe Landry🇨🇦

    Astrophysical observations of neutron stars probe the structure of dense nuclear matter and have the potential to reveal phase transitions at high densities. Most recent analyses are based on parametrized models of the equation of state with a finite number of parameters and occasionally include extra parameters intended to capture phase transition phenomenology. However, such models restrict the types of behavior allowed and may not match the true equation of state. We introduce a complementary approach that extracts phase transitions directly from the equation of state without relying on, and thus being restricted by, an underlying parametrization. We then constrain the presence of phase transitions in neutron stars with astrophysical data. Current pulsar mass, tidal deformability, and mass-radius measurements disfavor only the strongest of possible phase transitions (latent energy per particle ). Weaker phase transitions are consistent with observations. We further investigate the prospects for measuring phase transitions with future gravitational-wave observations and find that catalogs of \result{} events will (at best) yield Bayes factors of in favor of phase transitions even when the true equation of state contains very strong phase transitions. Our results reinforce the idea that neutron star observations will primarily constrain trends in macroscopic properties rather than detailed microscopic behavior. Fine-tuned equation of state models will likely remain unconstrained in the near future.

    Comments:
    18 pages (+12 pages of references and appendix), 17 figures, 5 tables
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2305.07411 [pdf]
    PRD(2023)·61 citations

Affiliations

first authorsco-authorsvia INSPIRE