Spectral properties of quarks above <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"><mml:msub><mml:mi>T</mml:mi><mml:mi>c</mml:mi></mml:msub></mml:math> in quenched lattice QCD

Karsch, Frithjof; Kitazawa, Masakiyo

doi:10.1016/j.physletb.2007.10.034

Cited by 26 publications

(20 citation statements)

References 32 publications

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“…Going into details or even listing a complete set of references just for Landau gauge is far beyond the scope of this review. It suffices to say that one can investigate from them a phletora of physical phenomena like, e. g., the dynamical generation of mass [14, 271, 272, 280, 355-358, 365, 366, 368, 369], chiral symmetry breaking and restoration at finite temperature [280,370,371], the deconfinement transition [249,[371][372][373][374], center observables like the Polyakov loop [249,375], conceptual access to the string tension [206][207][208]376], confinement of matter fields [206-208, 375, 377], color-superconducting phases at large densities [239,[378][379][380][381], the Higgs effect [25], and infrared conformality [6,26,382,383], only to mention some. However, already from the brief presentation in figure 36, it can be deduced that the presence …”

Section: Matter Fieldsmentioning

confidence: 99%

Gauge bosons at zero and finite temperature

2013

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Gauge theories of the Yang-Mills type are the single most important building block of the standard model of particle physics and beyond. They are an integral part of the strong and weak interactions, and in their Abelian version of electromagnetism. Since Yang-Mills theories are gauge theories their elementary particles, the gauge bosons, cannot be described without fixing a gauge. Therefore, to obtain their properties a quantized and gauge-fixed setting is necessary.Beyond perturbation theory, gauge-fixing in non-Abelian gauge theories is obstructed by the Gribov-Singer ambiguity, which requires the introduction of non-local constraints. The construction and implementation of a method-independent gauge-fixing prescription to resolve this ambiguity is the single most important first step to describe gauge bosons beyond perturbation theory. Proposals for such a procedure, generalizing the perturbative Landau gauge, are described here. Their implementation are discussed for two example methods, lattice gauge theory and the quantum equations of motion.After gauge-fixing, it is possible to study gauge bosons in detail. The most direct access is provided by their correlation functions. The corresponding two-and three-point correlation functions are presented at all energy scales. These give access to the properties of the gauge bosons, like their absence from the asymptotic physical state space, particle-like properties at high energies, and the running coupling. Furthermore, auxiliary degrees of freedom are introduced during gauge-fixing, and their properties are discussed as well. These results are presented for two, three, and four dimensions, and for various gauge algebras.Finally, the modifications of the properties of gauge bosons at finite temperature are presented. Evidence is provided that these reflect the phase structure of Yang-Mills theory. However, it is found that the phase transition is not deconfining the gauge bosons, although the bulk thermodynamical behavior is of a Stefan-Boltzmann type. The resolution of this apparent contradiction is also presented. In addition, this resolution provides an explicit and constructive solution to the Linde problem.Thus, the technical and conceptual framework presented here can be taken as a basis how to determine correlation functions in Yang-Mills theory, therefore opening up the avenue to investigate theories of direct practical relevance. The status of this effort will be briefly described, alongside with connections to other approaches to Yang-Mills theory beyond perturbation theory.

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Section: Matter Fieldsmentioning

confidence: 99%

Gauge bosons at zero and finite temperature

2013

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“…On the other hand such real-time properties can also be accessed via the spectral functions of the fundamental constituents of QCD, gluons and quarks; see e.g. [14,[19][20][21][22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Finite-temperature gluon spectral functions from $$N_f=2+1+1$$ N f = 2 + 1 + 1 lattice

et al. 2018

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We investigate gluon correlation functions and spectral functions at finite temperature in Landau gauge on lattice QCD ensembles with N f = 2 + 1 + 1 dynamical twisted-mass quarks flavors, generated by the tmfT collaboration. They cover a temperature range from 0.8 ≤ T /T C ≤ 4 using the fixed-scale approach. Our study of spectral properties is based on a novel Bayesian approach for the extraction of non-positive-definite spectral functions. For each binned spatial momentum we take into account the gluon correlation functions at all available discrete imaginary frequencies. Clear indications for the existence of a well defined quasiparticle peak are obtained. Due to a relatively small number of imaginary frequencies available, we focus on the momentum and temperature dependence of the position of this spectral feature. The corresponding dispersion relation reveals different in-medium masses for longitudinal and transversal gluons at high temperatures, qualitatively consistent with weak coupling expectations.

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“…In contrast to this another method has been established in Refs. [24,25]. There the authors assumed a certain shape for the quark spectral function including a few fitting parameters which were determined from the numerical data.…”

Section: Introductionmentioning

confidence: 99%

Quark spectral properties above T c from Dyson–Schwinger equations

2010

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We report on an analysis of the quark spectral representation at finite temperatures based on the quark propagator determined from its Dyson-Schwinger equation in Landau gauge. In Euclidean space we achieve nice agreement with recent results from quenched lattice QCD. We find different analytical properties of the quark propagator below and above the deconfinement transition. Using a variety of ansätze for the spectral function we then analyze the possible quasiparticle spectrum, in particular its quark mass and momentum dependence in the high temperature phase. This analysis is completed by an application of the Maximum Entropy Method, in principle allowing for any positive semi-definite spectral function. Our results motivate a more direct determination of the spectral function in the framework of Dyson-Schwinger equations.

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Spectral properties of quarks above Tc in quenched lattice QCD

Cited by 26 publications

References 32 publications

Gauge bosons at zero and finite temperature

Gauge bosons at zero and finite temperature

Finite-temperature gluon spectral functions from $$N_f=2+1+1$$ N f = 2 + 1 + 1 lattice

Quark spectral properties above T c from Dyson–Schwinger equations

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