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Nuclear Theory·nucl-th

Tuesday·February 8, 2022

9 papers—4 primary·5 cross-listed

All9Primary4Cross-lists5
  1. 05

    [Submitted on 5 Feb 2022] (cross-list from hep-ph)

    Entanglement entropy and flow in two dimensional QCD: parton and string duality

    Yizhuang Liu🇵🇱 · Maciej A. Nowak🇵🇱 · Ismail Zahed🇺🇸

    We discuss quantum entanglement between fast and slow degrees of freedom, in a two dimensional (2D) large gauge theory with Dirac quarks, quantized on the light front. Using the 't Hooft wave functions, we construct the reduced density matrix for an interval in the momentum fraction -space, and calculate its von Neumann entropy in terms of structure functions, that are measured by DIS on mesons (hadrons in general). We found that the entropy is bounded by an area law with logarithmic divergences, proportional to the rapidity of the meson. The evolution of the entanglement entropy with rapidity, is fixed by the cumulative singlet PDF, and bounded from above by a Kolmogorov-Sinai entropy of 1. At low-, the entanglement exhibits an asymptotic expansion, similar to the forward meson-meson scattering amplitude in the Regge limit. The evolution of the entanglement entropy in parton- per unit rapidity, measures the meson singlet PDF. The re-summed entanglement entropy along the single meson Regge trajectory, is string-like. We suggest that its extension to multi-meson states, models DIS scattering on a large 2D nucleus. The result, is a large rate of change of the entanglement entropy with rapidity, that matches the current Bekenstein-Bremermann bound for maximum quantum information flow. This mechanism may be at the origin of the large entropy deposition and rapid thermalization, reported in current heavy ion colliders, and may extend to future electron-ion colliders.

    Comments:
    22 pages, 0 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2202.02612 [pdf]
    PRD(2022)·23 citations
  2. 06

    [Submitted on 7 Feb 2022] (cross-list from hep-lat)

    Heavy quarks at finite temperature

    Johannes Heinrich Weber🇩🇪

    New incarnations of heavy-ion collision experiments are turning our attention to hard processes and a more fine-grained resolution of the QGP. In this endeavor quarkonia or open heavy flavors turn out to be versatile probes, which are usually described through models based on perturbative QCD, AdS, and effective field theories. The lattice provides nonperturbative input and constraints to such models.\newline In-medium bottomonia, the complex static quark-antiquark potential, and the heavy-quark momentum diffusion coefficient are key quantities where lattice gauge theory has recently achieved significant progress with impact for heavy-ion phenomenology. We review these lattice results, relate them to phenomenological applications, and close with an outlook.

    Comments:
    Write-up corresponding to my topical plenary talk in The 38th International Symposium on Lattice Field Theory, LATTICE2021 26th-30th July, 2021 Zoom/Gather@Massachusetts Institute of Technology; 22 pages, 4 figures
    Subjects:
    High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2202.03054 [pdf]
    PoS(2022)·1 citation
  3. 07

    [Submitted on 7 Feb 2022] (cross-list from physics.class-ph)

    Lorentz transformation in Maxwell equations for slowly moving media

    Xin-Li Sheng🇨🇳 · Yang Li🇨🇳 · Shi Pu🇨🇳 · Qun Wang🇨🇳

    We use the method of field decomposition, a technique widely used in relativistic magnetohydrodynamics, to study the small velocity approximation (SVA) of the Lorentz transformation in Maxwell equations for slowly moving media. The "deformed" Maxwell equations derived under the SVA in the lab frame can be put into the conventional form of Maxwell equations in the medium's comoving frame. Our results show that the Lorentz transformation in the SVA up to ( is the speed of the medium and is the speed of light in vacuum) is essential to derive these equations: the time and charge density must also change when transforming to a different frame even in the SVA, not just the position and current density as in the Galilean transformation. This marks the essential difference of the Lorentz transformation from the Galilean one. We show that the integral forms of Faraday and Ampere equations for slowly moving surfaces are consistent with Maxwell equations. We also present Faraday equation the covariant integral form in which the electromotive force can be defined as a Lorentz scalar independent of the observer's frame. No evidences exist to support an extension or modification of Maxwell equations.

    Comments:
    16 pages, 1 figure, 3 tables. Section VI is added about integral forms of Faraday and Ampere laws for moving surfaces. Part of Section IV and V are rewitten
    Subjects:
    physics.class-ph (physics.class-ph); Mesoscale and Nanoscale Physics (cond-mat.mes-hall); cond-mat.mtrl-sci (cond-mat.mtrl-sci); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2202.03122 [pdf]
    Symmetry(2022)·2 citations
  4. 08

    [Submitted on 7 Feb 2022] (cross-list from hep-ph)

    Scrutinizing scattering in light of recent lattice phase shifts

    Xiu-Li Gao🇨🇳 · Zhi-Hui Guo🇨🇳 · Zhiguang Xiao🇨🇳 · Zhi-Yong Zhou🇨🇳

    In this paper, the partial wave scattering phase shifts determined by the lattice QCD approach are analyzed by using a novel dispersive solution of the S-matrix, i.e. the PKU representation, in which the unitarity and analyticity of scattering amplitudes are automatically satisfied and the phase shifts are conveniently decomposed into the contributions of the cuts and various poles, including bound states, virtual states and resonances. The contribution of the left-hand cut is estimated by the chiral perturbation theory to . The Balanchandran-Nuyts-Roskies relations are considered as constraints to meet the requirements of the crossing symmetry. It is found that the scattering phase shifts obtained at MeV by Hadron Spectrum Collaboration (HSC) reveal the presence of both a bound state pole and a virtual state pole below the threshold rather than only one bound state pole for the . To reproduce the lattice phase shifts at MeV, a virtual-state pole in the channel is found to be necessary in order to balance the left-hand cut effects from the chiral amplitudes. Similar discussions are also carried out for the lattice results with MeV from HSC. The observed behaviors of the pole positions with respect to the variation of the pion masses can provide deep insights into our understanding of the dynamical origin of resonance.

    Comments:
    12 pages, 7 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
    arXiv:
    2202.03124 [pdf]
    PRD(2022)·13 citations
  5. 09

    [Submitted on 7 Feb 2022] (cross-list from hep-ph)

    Polarized Antimatter in the Proton from Global QCD Analysis

    C. Cocuzza🇺🇸 · W. Melnitchouk🇺🇸 · A. Metz🇺🇸 · N. Sato🇺🇸

    We present the first simultaneous global QCD analysis of spin-dependent parton distribution functions alongside their spin-averaged counterparts and pion, kaon, and unidentified hadron fragmentation functions. This analysis includes all data relevant for constraining the polarized light quark sea asymmetry , in particular the latest polarized -lepton production data from the STAR collaboration at RHIC and semi-inclusive deep inelastic scattering data from COMPASS, allowing the most robust extraction available with minimal theoretical assumptions. We also extract a self-consistent set of antiquark polarization ratios and and determine the signs of the truncated contributions to the proton spin from the light antiquarks.

    Comments:
    4 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
    arXiv:
    2202.03372 [pdf]
    PRD(2022)·67 citations

Affiliations

first authorsco-authorsvia INSPIRE