Quark localization by Polyakov loops in high temperature QCD

Kovács, Tamás; Bruckmann, Falk; Pittler, Ferenc; Schierenberg, Sebastian

doi:10.22323/1.139.0200

Cited by 5 publications

(7 citation statements)

References 8 publications

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“…There the (local) Polyakov loop is 1 nearly everywhere; however, there are defects where the Polyakov loop differs from 1. Also here the low eigenmodes of the Dirac operator become trapped around these defects, see [7].…”

Section: Introductionmentioning

confidence: 93%

Anderson localization in sigma models

Bruckmann

Wellnhofer

2018

EPJ Web Conf.

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Abstract. In QCD above the chiral restoration temperature there exists an Anderson transition in the fermion spectrum from localized to delocalized modes. We investigate whether the same holds for nonlinear sigma models which share properties like dynamical mass generation and asymptotic freedom with QCD. In particular we study the spectra of fermions coupled to (quenched) CP(N-1) configurations at high temperatures. We compare results in two and three space-time dimensions: in two dimensions the Anderson transition is absent, since all fermion modes are localized, while in three dimensions it is present. Our measurements include a more recent observable characterizing level spacings: the distribution of ratios of consecutive level spacings.

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Section: Introductionmentioning

confidence: 93%

Anderson localization in sigma models

Bruckmann

Wellnhofer

2018

EPJ Web Conf.

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“…In quenched QCD at high temperatures the spectral density of eigenstates (of the staggered Dirac operator) shows a square root behaviour [9], and the delocalization energy scale has been empirically identified using the inverse participation ratio (IPR) [10]. A clear correlation between the space-time density of the localized eigenmodes and the local Polyakov loop has been observed [11]. The modes close to the mobility edge possess a multifractal structure [12,13].…”

Section: Introductionmentioning

confidence: 97%

The Anderson transition in QCD with $N_f=2+1+1$ twisted mass quarks: overlap analysis

Holicki¹,

Ilgenfritz²,

Smekal³

2019

Proceedings of the 36th Annual International Symposium on Lattice Field Theory — PoS(LATTICE2018)

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Chiral Random Matrix Theory has proven to describe the spectral properties of low temperature QCD very well. However, at temperatures above the chiral symmetry restoring transition it can not provide a global description. The level-spacing distribution in the lower part of the spectrum of the Dirac operator is Poisson-like. There the eigenmodes are localized in space-time and separated from the rest of the spectrum by a so-called mobility edge. In analogy to Anderson localization in condensed-matter systems with random disorder this has been called the QCD-Anderson transition. Here, we study the localization features of the low-lying eigenmodes of the massless overlap operator on configurations generated with N f = 2 + 1 + 1 twisted mass Wilson sea quarks and present results concerning the temperature dependence of the mobility edge and the mechanism of the quark-mode localization. We have used various methods to fix the spectral position of the delocalization transition and verify that the mobility edge extrapolates to zero at a temperature within the chiral transition region.

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“…Another group [8] has also reported no gap at the origin but they have found that small eigenmodes, which mainly contribute to U(1) A breaking correlation functions, are localized and uncorrelated, suggesting that their contribution to the correlation functions is negligible. A simulation with overlap quarks [9], however, has reported the existence of a gap in the Dirac eigenvalue density and a degeneracy of pion and eta(-prime) meson correlators, which suggests the recovery of U(1) A symmetry.…”

Section: Introductionmentioning

confidence: 99%

Chiral symmetry restoration, the eigenvalue density of the Dirac operator, and the axial U(1) anomaly at finite temperature

2012

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We reconsider constraints on the eigenvalue density of the Dirac operator in the chiral symmetric phase of 2 flavor QCD at finite temperature. To avoid possible ultra-violet(UV) divergences, we work on a lattice, employing the overlap Dirac operator, which ensures the exact "chiral" symmetry at finite lattice spacings. Studying multi-point correlation functions in various channels and taking their thermodynamical limit (and then taking the chiral limit), we obtain stronger constraints than those found in the previous studies: both the eigenvalue density at the origin and its first and second derivatives vanish in the chiral limit of 2 flavor QCD. In addition we show that the axial U(1) anomaly becomes invisible in susceptibilities of scalar and pseudo scalar mesons, suggesting that the 2nd order chiral phase transition with the O(4) scaling is not realized in 2 flavor QCD.Possible lattice artifacts when non-chiral lattice Dirac operator is employed are briefly discussed.

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Quark localization by Polyakov loops in high temperature QCD

Cited by 5 publications

References 8 publications

Anderson localization in sigma models

Anderson localization in sigma models

The Anderson transition in QCD with $N_f=2+1+1$ twisted mass quarks: overlap analysis

Chiral symmetry restoration, the eigenvalue density of the Dirac operator, and the axial U(1) anomaly at finite temperature

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