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Nuclear Theory·nucl-th

Tuesday·February 28, 2017

12 papers—6 primary·6 cross-listed

All12Primary6Cross-lists6
  1. 07

    Quasinormal modes of charged magnetic black branes & chiral magnetic transport

    Martin Ammon🇩🇪 · Matthias Kaminski🇺🇸 · Roshan Koirala🇺🇸 · Julian Leiber🇩🇪 · Jackson Wu🇺🇸

    We compute quasinormal modes (QNMs) of the metric and gauge field perturbations about black branes electrically and magnetically charged in the Einstein-Maxwell-Chern-Simons theory. By the gauge/gravity correspondence, this theory is dual to a particular class of field theories with a chiral anomaly, in a thermal charged plasma state subjected to a constant external magnetic field, . The QNMs are dual to the poles of the two-point functions of the energy-momentum and axial current operators, and they encode information about the dissipation and transport of charges in the plasma. Complementary to the gravity calculation, we work out the hydrodynamic description of the dual field theory in the presence of a chiral anomaly, and a constant external . We find good agreement with the weak field hydrodynamics, which can extend beyond the weak regime into intermediate regimes. Furthermore, we provide results that can be tested against thermodynamics and hydrodynamics in the strong regime. We find QNMs exhibiting Landau level behavior, which become long-lived at large if the anomaly coefficient exceeds a critical magnitude. Chiral transport is analyzed beyond the hydrodynamic approximation for the five (formerly) hydrodynamic modes, including a chiral magnetic wave.

    ↳ hep-thhep-phnucl-thJHEP(2017)·54 citations
  2. 08

    What are the low- and large- boundaries of collinear QCD factorization theorems?

    E. Moffat🇺🇸 · W. Melnitchouk🇺🇸 · T. C. Rogers🇺🇸 · N. Sato🇺🇸

    Familiar factorized descriptions of classic QCD processes such as deeply-inelastic scattering (DIS) apply in the limit of very large hard scales, much larger than nonperturbative mass scales and other nonperturbative physical properties like intrinsic transverse momentum. Since many interesting DIS studies occur at kinematic regions where the hard scale, 1-2 GeV, is not very much greater than the hadron masses involved, and the Bjorken scaling variable is large, , it is important to examine the boundaries of the most basic factorization assumptions and assess whether improved starting points are needed. Using an idealized field-theoretic model that contains most of the essential elements that a factorization derivation must confront, we retrace the steps of factorization approximations and compare with calculations that keep all kinematics exact. We examine the relative importance of such quantities as the target mass, light quark masses, and intrinsic parton transverse momentum, and argue that a careful accounting of parton virtuality is essential for treating power corrections to collinear factorization. We use our observations to motivate searches for new or enhanced factorization theorems specifically designed to deal with moderately low- and large- physics.

    ↳ hep-phhep-exnucl-thPRD(2017)·21 citations
  3. 09

    Event-by-event mean fluctuations and transverse size of color flux tube generated in - collisions at =0.90TeV

    Takeshi Osada🇯🇵 · Masamichi Ishihara🇯🇵

    We propose a novel phenomenological model of mean transverse momentum fluctuations based on the Geometrical Scaling hypothesis. Bose-Einstein correlations between two gluons generated from an identical color flux tube are taken into account as a source of the fluctuation. We calculate an event-by-event fluctuation measure and show that ALICE data observed at 0.90 TeV for + collisions are reproduced. By fitting our model to the experimental data, we evaluate the transverse size of the color flux tube as a function of the multiplicity.

    ↳ hep-phnucl-thJ.Phys.G(2018)·13 citations
  4. 10

    Effective Model of QCD Magnetic Monopoles From Numerical Study of One- and Two-Component Coulomb Quantum Bose Gases

    Adith Ramamurti🇺🇸 · Edward Shuryak🇺🇸

    Magnetic monopoles are suggested to play an important role in strongly coupled quark-gluon plasma (sQGP) near the deconfinement temperature. So far, their many-body treatment has only been done classically, with just binary scattering solved in quantum mechanics. In this paper we start quantum many-body studies of the monopole ensembles. Specifically, we carry out numerical simulations of the path integral for one- and two-component Coulomb Bose systems. We determine the relation between the critical temperature for the Bose-Einstein condensation phase transition and the Coulomb coupling strength using two methods, the classic finite-size scaling of the condensate and a lattice-tested method based on permutation cycles. For a one-component Coulomb Bose gas, we observe the same behavior of the critical temperature -- initially rising slightly then falling as interaction strength is increased -- as seen in the case of hard spheres; we also observe the same behavior for a two-component Coulomb Bose gas. We then calculate sets of radial correlation functions between the like and unlike charged particles. By matching those with the correlation functions previously calculated on the lattice, we derive an effective quantum model of color magnetic monopoles in QCD. From this matched model, we are able to extract the monopole contribution to QCD equation of state near .

    ↳ hep-phhep-latnucl-thPRD(2017)·10 citations
  5. 11

    Fluctuations In The Inhomogeneous Chiral Transition

    T. Tatsumi🇯🇵 · R. Yoshiike🇯🇵 · T.-G. Lee🇯🇵

    Chiral pair fluctuation are considered near the phase boundary of the inhomogeneous chiral phase (iCP). The fluctuations are then bosonized and an effective action for the chiral pair fluctuation is basically constructed by considering the ring diagram of the polarization function. We can evaluate the self-energy and effective four point interaction among fluctuations in a consistent way. The peculiar dispersion of the fluctuation, reflecting the spatially inhomogeneous transition, gives rise to interesting and qualitative results. Thermal fluctuations prohibit the second-order transition, while the effect of the quantum fluctuations is rather modest. Quantum and thermal fluctuations changes the second-order transition to the first one by changing the sign of the effective four-point interaction between effective mesons. These features may be observed by relativistic heavy-ion collisions through the analysis of the thermodynamic observables. Distinct from the second-order phase transition, the first moment such as entropy production exhibits an anomalous behavior due to fluctuations, which is one of the signals of the phase transition to iCP. Some similar aspects are also remarked between iCP and the FFLO state in superconductivity.

    ↳ hep-phnucl-thPoS(2017)·0 citations
  6. 12

    Hybrid Quark Stars With Strong Magnetic Field

    T. Tatsumi🇯🇵 · H. Sotani🇯🇵

    Discovery of huge magnetic field in magnetars has stimulated a renewed interest about the magnetic field and physics of compact stars, where microphysics such as QED or QCD may play active parts. Here we discuss the equation of state (EOS) of quark matter in the core of compact stars by taking into account the strong magnetic field. We show that quark EOS becomes very stiff in the presence of the strong magnetic field, and becomes stiffest under the causality condition beyond the threshold strength of G. This is because quarks make the Landau levels in the presence of the magnetic field and thereby only the lowest Landau level is occupied in the extreme case beyond . Thus quarks can freely move along the magnetic field with localization in the perpendicular plane, which resembles the quasi-one dimensional systems and gives rise to a stiff EOS. Consequently, we may easily produce high-mass stars beyond two solar mass. As another interesting possibility, we discuss the appearance of the third family of compact stars, succeeding white dwarfs and neutron stars, before collapsing into black holes. We demonstrate an example, which is specified by a discontinuous increase of the adiabatic index at the hadron-quark phase transition. Such new family may affect the supernova explosions or the gravitational wave emitted from the neutron star mergers.

    ↳ astro-ph.HEhep-phnucl-thPoS(2017)·0 citations

Affiliations

first authorsco-authorsvia INSPIRE