Real-time correlation functions in the $$O(N)$$ O ( N ) model from the functional renormalization group

Kamikado, Kazuhiko; Strodthoff, Nils; Smekal, Lorenz von; Wambach, J.

doi:10.1140/epjc/s10052-014-2806-6

Cited by 71 publications

(125 citation statements)

References 35 publications

(68 reference statements)

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“…The mesonic fluctuations dominate the flow at T = µ = 0. In purely mesonic O(N )-models, on the other hand, the difference between pole and curvature masses is known to be a few percent effect and hence negligible [48,52]. We therefore neglect this discrepancy here as well and use the standard curvature masses to fix the parameters in our calculations.…”

Section: B Construction Of the Parity-doublet Modelmentioning

confidence: 99%

Chiral mirror-baryon-meson model and nuclear matter beyond mean-field approximation

2015

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We consider a chiral baryon-meson model for nucleons and their parity partners in mirror assignment interacting with pions, sigma and omega mesons to describe the liquid-gas transition of nuclear matter together with chiral symmetry restoration in the high density phase. Within the mean-field approximation the model is known to provide a phenomenologically successful description of the nuclear-matter transition. Here, we go beyond this approximation and include mesonic fluctuations by means of the functional renormalization group. While these fluctuations do not lead to major qualitative changes in the phase diagram of the model, beyond mean-field, one is no-longer free to adjust the parameters so as to reproduce the binding energy per nucleon, the nuclear saturation density, and the nucleon sigma term all at the same time. However, the prediction of a clear first-order chiral transition at low temperatures inside the high baryon-density phase appears to be robust.

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Section: B Construction Of the Parity-doublet Modelmentioning

confidence: 99%

Chiral mirror-baryon-meson model and nuclear matter beyond mean-field approximation

2015

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“…Using (26) with the explicit expressions of the zeroth order propagators (25), one finds, after some elementary algebra,…”

Section: Lpa For the Gross-neveu Modelmentioning

confidence: 99%

Local potential approximation for the renormalization group flow of fermionic field theories

Jakovác

Patkós

2013

Phys. Rev. D

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The second functional derivative of the effective potential of pure fermionic field theories is rewritten in a factorized form, which facilitates the evaluation of the renormalization flow rate of the effective action in the Wetterich equation. It is applied to the local potential approximation in cases when the effective potential depends on scalar composites built from the fermions. The procedure is demonstrated explicitly on the example of the N f -flavor Gross-Neveu model and the one-flavor chiral Nambu-Jona-Lasinio model.

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“…Even though first computations in this direction have been performed e.g. in [20,21], we shall utilise Euclidean correlation functions within a numerical analytic continuation.In this work we study the shear viscosity over entropy ratio η/s in pure SU (3) Landau gauge Yang-Mills (YM) theory within the approach set-up in [9]. In the present…”

mentioning

confidence: 99%

Transport Coefficients in Yang-Mills Theory and QCD

et al. 2015

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We calculate the shear viscosity over entropy density ratio η/s in Yang-Mills theory from the Kubo formula using an exact diagrammatic representation in terms of full propagators and vertices using gluon spectral functions as external input. We provide an analytic fit formula for the temperature dependence of η/s over the whole temperature range from a glueball resonance gas at low temperatures, to a high-temperature regime consistent with perturbative results. Subsequently we provide a first estimate for η/s in QCD.PACS numbers: 12.38. Aw, 11.10.Wx , 11.15.Tk Introduction -The experimental heavy-ion programs at RHIC [1,2] and at the LHC [3] explore the physics of the quark-gluon plasma (QGP). It turns out that the dynamics of the hot plasma created in heavy-ion collisions is well-described by hydrodynamics. Therefore, the determination of transport coefficients in the QGP is of great interest. One aspect is that the inference of the initial state physics requires a precise description of the hydrodynamical evolution, which in turn depends on transport coefficients as microscopic input, [4]. In particular, the viscosity over entropy ratio η/s governs the efficiency of the conversion of the initial spatial anisotropy into a momentum anisotropy of the final state.For the determination of η/s and its temperature dependence in the quark-gluon plasma, theoretical approaches face several challenges.The temperature regimes below and above the critical temperature T c are characterised by different degrees of freedom, and for temperatures T 2T c non-perturbative effects become important. Of particular interest is the vicinity of T c , where the minimum for η/s is expected [5,6]. A universal lower bound for η/s of 1/4π was conjectured in [7] using the AdS/CFT correspondence. Indeed, measurements of the elliptic flow v 2 indicate a value for η/s which is of the order of this lower bound [8]. The bound has been tested theoretically with several methods for the QGP [9-15], but also for other potentially perfect liquids, such as ultracold atoms [16][17][18].The Kubo formulae relate η to the energy-momentum tensor (EMT) [19]. Spectral functions are real-time quantities and cannot be obtained directly from Euclidean correlation functions. However, the direct calculation of real-time correlation functions represents a notoriously difficult problem in non-perturbative approaches to quantum field theory. Even though first computations in this direction have been performed e.g. in [20,21], we shall utilise Euclidean correlation functions within a numerical analytic continuation.In this work we study the shear viscosity over entropy ratio η/s in pure SU (3) Landau gauge Yang-Mills (YM) theory within the approach set-up in [9]. In the present

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Real-time correlation functions in the $$O(N)$$ O ( N ) model from the functional renormalization group

Cited by 71 publications

References 35 publications

Chiral mirror-baryon-meson model and nuclear matter beyond mean-field approximation

Chiral mirror-baryon-meson model and nuclear matter beyond mean-field approximation

Local potential approximation for the renormalization group flow of fermionic field theories

Transport Coefficients in Yang-Mills Theory and QCD

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