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Nuclear Theory·nucl-th

Wednesday·May 7, 2025

13 papers—6 primary·7 cross-listed

All13Primary6Cross-lists7
  1. 07

    [Submitted on 4 May 2025] (cross-list from hep-lat)

    Gauge invariance and color charge fluctuations

    Thomas D. Cohen🇺🇸

    The nature of confinement is connected with color charge. Unfortunately, the color charge densities in QCD, the Noether charge densities associated with the global color invariance, are not invariant under local color rotations. This implies that the expectation values of the net color charge in any region of any physical state in QCD, states that satisfy the color Gauss law, are automatically zero for all components of color. In this paper it is shown that the expectation value of the square of the net color charge in a region, a measure of the color charge fluctuations, is necessarily nonzero when evaluated in physical states and the result, while depending on the scheme and scale by which the theory is regulated, is gauge invariant. This holds despite the formal lack of gauge invariance of the operator. Moreover, there is a particular combination of the color charge fluctuations for the vacuum and for a system describable by a non-trivial density matrix that is independent that has a well-defined continuum limit

    Comments:
    4 pages; clarifying remarks added; minor error fixed
    Subjects:
    High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
    arXiv:
    2505.02102 [pdf]
    PRC(2025)·0 citations
  2. 08

    [Submitted on 5 May 2025] (cross-list from hep-lat)

    Pole-Expansion of Two-Hadron Imaginary-Time Correlation Function -a new method of analysis for unstable states in lattice QCD-

    Wren Yamada🇯🇵 · Osamu Morimatsu🇯🇵 · Toru Sato🇯🇵 · Koichi Yazaki🇯🇵

    We analyze the pole expansion of the two-hadron imaginary-time correlation function. We first explain the general idea that the imaginary-time correlation function is expressed as a sum of the pole terms, the Mittag-Leffler expansion, in terms of the uniformization variable, which makes the S-matrix single-valued. We then derive explicit expressions of the pole expansion for the single-channel ( meson) and two-channel () examples and demonstrate that the pole expansion actually holds employing phenomenological models, the vector-dominance model for the meson and the chiral unitary model for . From this observation we propose the pole expansion as a method to extract information of unstable states such as masses and widths from the two-hadron imaginary-time correlation functions obtained by lattice QCD simulations.

    Comments:
    16 pages, 8 figures
    Subjects:
    High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
    arXiv:
    2505.02878 [pdf]
    PRD(2025)·2 citations
  3. 09

    [Submitted on 5 May 2025] (cross-list from quant-ph)

    Stabilizer-Accelerated Quantum Many-Body Ground-State Estimation

    Caroline E. P. Robin🇩🇪

    We investigate how the stabilizer formalism, in particular highly-entangled stabilizer states, can be used to describe the emergence of many-body shape collectivity from individual constituents, in a symmetry-preserving and classically efficient way. The method that we adopt is based on determining an optimal separation of the Hamiltonian into a stabilizer component and a residual part inducing non-stabilizerness. The corresponding stabilizer ground state is efficiently prepared using techniques of graph states and stabilizer tableaux. We demonstrate this technique in context of the Lipkin-Meshkov-Glick model, a fully-connected spin system presenting a second order phase transition from spherical to deformed state. The resulting stabilizer ground state is found to capture to a large extent both bi-partite and collective multi-partite entanglement features of the exact solution in the region of large deformation. We also explore several methods for injecting non-stabilizerness into the system, including ADAPT-VQE, and imaginary-time evolution (ITE) techniques. Stabilizer ground states are found to accelerate ITE convergence due to a larger overlap with the exact ground state. While further investigations are required, the present work suggests that collective features may be associated with high but simple large-scale entanglement which can be captured by stabilizer states, while the interplay with single-particle motion may be responsible for inducing non-stabilizerness. This study motivates applications of the proposed approach to more realistic quantum many-body systems, whose stabilizer ground states can be used in combinations with powerful classical many-body techniques and/or quantum methods.

    Comments:
    25 pages, 10 figures. v2: minor modifications, references added, v3: accepted version
    Subjects:
    Quantum Physics (quant-ph); Strongly Correlated Electrons (cond-mat.str-el); Nuclear Theory (nucl-th)
    arXiv:
    2505.02923 [pdf]
    PRA(2025)·14 citations
  4. 10

    [Submitted on 5 May 2025] (cross-list from astro-ph.HE)

    A Continuous Galactic Line Source of Axions: The Remarkable Case of 23Na

    W. C. Haxton🇺🇸 · Xing Liu🇺🇸 · Annie McCutcheon🇺🇸 · Anupam Ray🇺🇸

    We argue that Na is a potentially significant source of galactic axions. For temperatures K -- characteristic of carbon burning in the massive progenitors of supernovae and ONeMg white dwarfs -- the 440 keV first excited state of Na is thermally populated, with its repeated decays pumping stellar energy into escaping axions. Odd-A nuclear abundances are typically very low in high-temperature stellar environments (or absent entirely due to burn-up). Na is an exception: of the isotope is synthesized during carbon burning then maintained at K for times ranging up to y. Using MESA simulations, a galactic model, and sampling over progenitor masses, locations, and evolutionary stages, we find a continuous flux at earth of /cms for . Some fraction of these axions convert to photons as they propagate through the galactic magnetic field, producing a distinctive 440 keV line ray detectable by all-sky detectors like the Compton Spectrometer and Imager (COSI). Assuming a 1G galactic magnetic field and a sufficiently light axion mass, we find that COSI will be able to probe GeV at after two years of surveying.

    Comments:
    6 pages, 4 figures; updated to reflect the published version
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2505.03038 [pdf]
    PRL(2025)·5 citations
  5. 11

    [Submitted on 5 May 2025] (cross-list from hep-ph)

    Study of octupole deformations in Pb-Pb collisions at 5.02 TeV

    Saraswati Pandey🇮🇳 · B.K. Singh🇮🇳

    In this letter, we present the study of the role of octupole deformation in non-spherical nuclei in most-central Pb--Pb collisions at the LHC energy regime. The sensitivity of octupole deformation to the QGP observables is presented by employing the Monte Carlo HYDJET++ model. Motivated by the discrepancies in the -to- puzzle found in Pb--Pb collisions and the low-energy nuclear structure calculations of nuclear deformation, we studied the first basic observables necessary for any study in heavy-ion collisions. Using the HYDJET++ framework, we calculate the pseudorapidity distribution, transverse momentum () spectra, and average anisotropic flow ( and ) of primary charged hadrons with different parameters in two geometrical configurations: body-body and tip-tip types of Pb--Pb collisions. The kinematic ranges and are considered. We observe that the charged hadron multiplicity and transverse momentum spectra are dependent on the strength of the octupole deformation parameter. The and in body-body collisions show a weak positive correlation with , while the average anisotropic flow in tip-tip collisions is weakly correlated with in the most-central collision region.

    Comments:
    5 pages, 7 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2505.03055 [pdf]
    PLB(2024)·0 citations
  6. 12

    [Submitted on 6 May 2025] (cross-list from quant-ph)

    Digital quantum simulations of scattering in quantum field theories using W states

    Roland C. Farrell🇺🇸 · Nikita A. Zemlevskiy🇺🇸 · Marc Illa🇺🇸 · John Preskill🇺🇸

    High-energy particle collisions can convert energy into matter through the inelastic production of new particles. Quantum computers are an ideal platform for simulating the out-of-equilibrium dynamics of collisions and the formation of subsequent many-particle states. In this work, evidence for inelastic particle production is observed in one-dimensional Ising field theory using IBM's quantum computers. The scattering experiment is performed on 104 qubits of ibm_marrakesh and uses up to 5,589 two-qubit gates to access the post-collision dynamics. An outgoing heavy particle produced in the collision is identified from the skewness of the measured energy density. Integral to this computation is a new quantum algorithm for preparing the initial state (wavepackets) of a quantum field theory scattering simulation. This method efficiently prepares wavepackets by extending recent protocols for creating W states with mid-circuit measurement and feedforward. The required circuit depth is independent of wavepacket size and spatial dimension, representing a superexponential improvement over previous methods. Our wavepacket preparation algorithm can be applied to a wide range of lattice models and is demonstrated in one-dimensional Ising field theory, scalar field theory, the Schwinger model and two-dimensional Ising field theory.

    Comments:
    54 pages, 30 figures, 12 tables
    Subjects:
    Quantum Physics (quant-ph); High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2505.03111 [pdf]
    66 citations
  7. 13

    [Submitted on 6 May 2025] (cross-list from physics.data-an)

    A Centrality-independent Framework for Revealing Genuine Higher-Order Cumulants in Heavy-Ion Collisions

    Zhaohui Wang🇨🇳 · Xiaofeng Luo🇨🇳

    We propose a novel centrality definition-independent method for analyzing higher-order cumulants, specifically addressing the challenge of volume fluctuations that dominate in low-energy heavy-ion collisions. This method reconstructs particle number distributions using the Edgeworth expansion, with parameters optimized via a combination of differential evolution algorithm and Bayesian inference. Its effectiveness is validated using UrQMD model simulations and benchmarked against traditional approaches, including centrality definitions based on particle multiplicity. Our results show that the proposed framework yields cumulant patterns consistent with those obtained using number of participant nucleon () based centrality observables, while eliminating the conventional reliance on centrality determination. This consistency confirms the method's ability to extract genuine physical signals, thereby paving the way for probing the intrinsic thermodynamic properties of the produced medium through event-by-event fluctuations.

    Comments:
    15 pages, 13 figures
    Subjects:
    Data Analysis, Statistics and Probability (physics.data-an); High Energy Physics — Experiment (hep-ex); High Energy Physics — Theory (hep-th); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2505.03666 [pdf]
    PLB(2025)·8 citations

Affiliations

first authorsco-authorsvia INSPIRE