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Nuclear Theory·nucl-th

Friday·March 22, 2019

5 papers—2 primary·3 cross-listed

All5Primary2Cross-lists3
  1. 03

    [Submitted on 20 Mar 2019] (cross-list from hep-lat)

    General Methods for Digital Quantum Simulation of Gauge Theories

    Henry Lamm🇺🇸 · Scott Lawrence🇺🇸 · Yukari Yamauchi (for the NuQS Collaboration)🇺🇸

    A general scheme is presented for simulating gauge theories, with matter fields, on a digital quantum computer. A Trotterized time-evolution operator that respects gauge symmetry is constructed, and a procedure for obtaining time-separated, gauge-invariant operators is detailed. We demonstrate the procedure on small lattices, including the simulation of a 2+1D non-Abelian gauge theory.

    Comments:
    13 pages, 7 figures, v3 includes clarifying comments, additional data and additional references. Matched published version
    Subjects:
    High Energy Physics — Lattice (hep-lat); Strongly Correlated Electrons (cond-mat.str-el); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
    arXiv:
    1903.08807 [pdf]
    PRD(2019)·195 citations
  2. 04

    [Submitted on 21 Mar 2019] (cross-list from astro-ph.HE)

    New Neutron Star Equation of State with Quark-Hadron Crossover

    Gordon Baym🇺🇸 · Shun Furusawa🇯🇵 · Tetsuo Hatsuda🇯🇵 · Toru Kojo🇨🇳 · Hajime Togashi🇯🇵

    We present a much improved equation of state for neutron star matter, QHC19, with a smooth crossover from the hadronic regime at lower densities to the quark regime at higher densities. We now use the Togashi et al.~equation of state (Togashi:2017), a generalization of the Akmal-Pandharipande-Ravenhall equation of state of uniform nuclear matter, in the entire hadronic regime; the Togashi equation of state consistently describes non-uniform as well as uniform matter, and matter at beta equilibrium without the need for an interpolation between pure neutron and symmetric nuclear matter. We describe the quark matter regime at higher densities with the Nambu--Jona--Lasinio model, now identifying tight constraints on the phenomenological universal vector repulsion between quarks and the pairing interaction between quarks arising from the requirements of thermodynamic stability and causal propagation of sound. The resultant neutron star properties agree very well with the inferences of the LIGO/Virgo collaboration, from GW170817, of the pressure vs. baryon density, neutron star radii, and tidal deformabilities. The maximum neutron star mass allowed by QHC19 is 2.35 , consistent with all neutron star mass determinations.

    Comments:
    8 pages, 11 figures; v3) published version, appendix was added
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1903.08963 [pdf]
    ApJ(2019)·220 citations
  3. 05

    [Submitted on 21 Mar 2019] (cross-list from astro-ph.HE)

    Evidence for quark-matter cores in massive neutron stars

    Eemeli Annala🇫🇮 · Tyler Gorda🇺🇸 · Aleksi Kurkela🇨🇭 · Joonas Nättilä🇸🇪 · Aleksi Vuorinen🇫🇮

    The theory governing the strong nuclear force, Quantum Chromodynamics, predicts that at sufficiently high energy densities hadronic nuclear matter undergoes a deconfinement transition to a new phase of quarks and gluons. Although this has been observed in ultrarelativistic heavy-ion collisions, it is currently an open question whether quark matter exists inside neutron stars. By combining astrophysical observations and theoretical ab-initio calculations in a model-independent way, we find that the inferred properties of matter in the cores of neutron stars with mass corresponding to 1.4 solar masses are compatible with nuclear model calculations. However, the matter in the interior of maximally massive, stable neutron stars exhibits characteristics of the deconfined phase, which we interpret as evidence for the presence of quark-matter cores. For the heaviest reliably observed neutron stars with masses of about two solar masses, the presence of quark matter is found to be linked to the behaviour of the speed of sound c_s in strongly interacting matter. If the conformal bound (c_s)^2 < 1/3 is not strongly violated, massive neutron stars are predicted to have sizable quark-matter cores. This finding has important implications for the phenomenology of neutron stars, and affects the dynamics of neutron star mergers with at least one sufficiently massive participant.

    Comments:
    34 pages, including 8 pages main text + 10 pages methods; 8 figures. 3 EoS tables included as ancillary files. v2: Substantial changes from v1. Text shortened, with major changes to analysis and structure. Analysis and conclusions made more precise; title changed. Version accepted for publication in Nature Physics
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1903.09121 [pdf]
    Nat.Phys.(2020)·814 citations

Affiliations

first authorsco-authorsvia INSPIRE