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Nuclear Theory·nucl-th

Wednesday·July 6, 2022

9 papers—5 primary·4 cross-listed

All9Primary5Cross-lists4
  1. 06

    [Submitted on 4 Jul 2022] (cross-list from astro-ph.HE)

    Strong-field magnetohydrodynamics for neutron stars

    Shreya Vardhan · Sašo Grozdanov · Samuel Leutheusser · Hong Liu

    We present a formulation of magnetohydrodynamics which can be used to describe the evolution of strong magnetic fields in neutron star interiors. Our approach is based on viewing magnetohydrodynamics as a theory with a one-form global symmetry and developing an effective field theory for the hydrodynamic modes associated with this symmetry. In the regime where the local velocity and temperature variations can be neglected, we derive the most general constitutive relation consistent with symmetry constraints for the electric field in the presence of a strong magnetic field. This constitutive relation not only reproduces the phenomena of Ohmic decay, ambipolar diffusion, and Hall drift derived in a phenomenological model by Goldreich and Reisenegger, but also reveals new terms in the evolution of the magnetic field which cannot easily be seen from such microscopic models. This formulation gives predictions for novel diffusion behaviors of small perturbations around a constant background magnetic field, and for the two-point correlation functions among various components of the electric and magnetic fields.

    Comments:
    5+7 pages, 4 figures. Added in v2: comments on physical interpretation of the two new terms that appear in the constitutive relation for the magnetic field compared to earlier work of Goldreich and Reisenegger, and reference to arXiv:2408.12868 for the derivation of the effective action. Typos corrected. v3: Title changed to match published version
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th); Plasma Physics (physics.plasm-ph)
    arXiv:
    2207.01636 [pdf]
    PRResearch(2024)·19 citations
  2. 07

    [Submitted on 4 Jul 2022] (cross-list from hep-ph)

    Reevaluation of heavy-fermion-induced electron EDM at three loops

    Yohei Ema🇺🇸 · Ting Gao🇺🇸 · Maxim Pospelov🇺🇸

    Motivated by improved limits on electric dipole moments (EDMs), we revisit the three-loop light-by-light mechanism that transmits violation from a heavy fermion to a light one. Applying it to the electron EDM induced by EDMs of heavier flavors, we find additional contributions at the order or that were missing before and that make the result 1.4 times larger. Consequently we improve bounds on the tau EDM, and update indirect limits on the muon EDM as well as charm and bottom quark color EDMs.

    Comments:
    8 pages, 2 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
    arXiv:
    2207.01679 [pdf]
    PLB(2022)·17 citations
  3. 08

    [Submitted on 4 Jul 2022] (cross-list from quant-ph)

    Preparations for Quantum Simulations of Quantum Chromodynamics in 1+1 Dimensions: (I) Axial Gauge

    Roland C. Farrell🇺🇸 · Ivan A. Chernyshev🇺🇸 · Sarah J. M. Powell🇨🇦 · Nikita A. Zemlevskiy🇺🇸 · Marc Illa🇺🇸 · Martin J. Savage🇺🇸

    Tools necessary for quantum simulations of dimensional quantum chromodynamics are developed. When formulated in axial gauge and with two flavors of quarks, this system requires 12 qubits per spatial site with the gauge fields included via non-local interactions. Classical computations and D-Wave's quantum annealer Advantage are used to determine the hadronic spectrum, enabling a decomposition of the masses and a study of quark entanglement. Color edge states confined within a screening length of the end of the lattice are found. IBM's 7-qubit quantum computers, ibmq_jakarta and ibm_perth, are used to compute dynamics from the trivial vacuum in one-flavor QCD with one spatial site. More generally, the Hamiltonian and quantum circuits for time evolution of dimensional gauge theory with flavors of quarks are developed, and the resource requirements for large-scale quantum simulations are estimated.

    Comments:
    53 pages, 29 figures. Typo fixed in v3
    Subjects:
    Quantum Physics (quant-ph); High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2207.01731 [pdf]
    PRD(2023)·166 citations
  4. 09

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

    The Anomalous Magnetic Moment of the Muon: Beyond the Standard Model via Chiral Enhancement

    Andreas Crivellin🇨🇭 · Martin Hoferichter🇨🇭

    The anomalous magnetic moment of the muon displays a tension with the Standard-Model prediction, if data are used for hadronic vacuum polarization. In these proceedings we review possible explanations of this anomaly in terms of heavy new particles. As the necessary effect is of the order of the electroweak Standard-Model contribution, viable explanations with TeV-scale physics must involve an enhancement factor; in particular, one can obtain the chirality flip of the dipole operator via a sizable coupling to the Higgs doublet instead of the small muon Yukawa coupling. Such Standard-Model extensions then also predict effects in Higgs and -boson decays to muons, with details depending on the representations of the new particles. We first review the general case of chirally enhanced new physics, before discussing in more detail the concrete example of leptoquark models.

    Comments:
    8 pages, 3 figures, proceedings for: Les Rencontres de Physique de la Vallée d'Aoste 2022
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
    arXiv:
    2207.01912 [pdf]
    Nuovo Cim.C(2022)·5 citations

Affiliations

first authorsco-authorsvia INSPIRE