Trying to constrain the location of the QCD critical endpoint with lattice simulations

Fodor, Z.; Giordano, Matteo; Günther, Jana; Kapas, Kornel; Katz, Sándor D.; Pásztor, Attila; Portillo, Israel; Ratti, Claudia; Sexty, Dénes; Szabó, Kornélia

doi:10.1016/j.nuclphysa.2018.12.015

Cited by 25 publications

(16 citation statements)

References 8 publications

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“…In any case, our analysis within CEM-LQCD and CEM-HRG shows no evidence for the existence of a phase transition or a critical point at real µ B /T < r µ/T , with r µ/T ⇡ at all temperatures considered. This is consistent with all available lattice results at zero and imaginary chemical potential, but in contrast to various other QCD critical point estimates available in the literature: these are based on lattice reweighting techniques [44], experimental finitesize scaling analyses [45], the Dyson-Schwinger [46] or holographic [47,48] approaches, which are also shown in Fig. 4.…”

Section: The Radius Of Convergencesupporting

confidence: 89%

“…In this normalization (which follows Ref. [45]), ⌃¯ = 1 at T = µ I = 0 due to the Gell-Mann-Oakes-Renner relation. In addition, zero-temperature leading-order PT [7] predicts a gradual rotation of the condensates so that ⌃ 2 + ⌃ 2 ⇡ = 1 holds irrespective of µ I , which can also be observed to some extent in the full theory.…”

Section: Ii3 Observables and Renormalizationmentioning

confidence: 82%

“…H v D X n Z D O H 8 A f O 5 w / e m Y / L < / l a t e x i t > Baryon number fluctuations χ B 4 , χB 6 from the lattice in comparison with CEM, RFM models[44] (left, middle), and χ B 8 fitted with a polynomial model without criticality[45] (right).…”

mentioning

confidence: 99%

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Constraining the phase diagram of QCD at finite temperature and density

Philipsen¹

2020

Proceedings of 37th International Symposium on Lattice Field Theory — PoS(LATTICE2019)

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Section: The Radius Of Convergencesupporting

confidence: 89%

Section: Ii3 Observables and Renormalizationmentioning

confidence: 82%

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Constraining the phase diagram of QCD at finite temperature and density

Philipsen¹

2020

Proceedings of 37th International Symposium on Lattice Field Theory — PoS(LATTICE2019)

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“…The radius of convergence of the Taylor expansion in µ B is one of the most sought-after quantities in the finite temperature QCD community [25,38,[75][76][77][78]. The main reason is that it gives a lower bound on the location of the critical endpoint, and also that it gives us insight in how far one can trust the equation of state calculated from a Taylor expansion around µ B = 0.…”

Section: Discussionmentioning

confidence: 99%

Radius of convergence in lattice QCD at finite μB with rooted staggered fermions

et al. 2020

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In typical statistical mechanical systems the grand canonical partition function at finite volume is proportional to a polynomial of the fugacity e µ T . The zero of this Lee-Yang polynomial closest to the origin determines the radius of convergence of the Taylor expansion of the pressure around µ = 0. The computationally cheapest formulation of lattice QCD, rooted staggered fermions, with the usual definition of the rooted determinant, does not admit such a Lee-Yang polynomial. We show that the radius of convergence is then bounded by the spectral gap of the reduced matrix of the unrooted staggered operator. We suggest a new definition of the rooted staggered determinant at finite chemical potential that allows for a definition of a Lee-Yang polynomial, and therefore of the numerical study of Lee-Yang zeros. We also describe an algorithm to determine the Lee-Yang zeros and apply it to configurations generated with the 2-stout improved staggered action at Nt = 4. We perform a finite volume scaling study of the leading Lee-Yang zeros and estimate the radius of convergence of the Taylor expansion extrapolated to an infinite volume. We show that the limiting singularity is not on the real line, thus giving a lower bound on the location of any possible phase transitions at this lattice spacing. In the vicinity of the crossover temperature at zero chemical potential, the radius of convergence turns out to be at µ B T ≈ 2 and roughly temperature independent.

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“…Similarly, the pressure is shown in Fig. 6 for two different lattice spacings and N c ∈ [3,9]. Since this is far from the large N c limit, we explicitly checked that the first subleading contribution goes as ∼ N 0 c .…”

Section: Approaching the Continuummentioning

confidence: 96%

QCD in the heavy dense regime for general Nc: on the existence of quarkyonic matter

Philipsen¹,

Scheunert²

2019

J. High Energ. Phys.

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Lattice QCD with heavy quarks reduces to a three-dimensional effective theory of Polyakov loops, which is amenable to series expansion methods. We analyse the effective theory in the cold and dense regime for a general number of colours, N c . In particular, we investigate the transition from a hadron gas to baryon condensation. For any finite lattice spacing, we find the transition to become stronger, i.e. ultimately first-order, as N c is made large. Moreover, in the baryon condensed regime, we find the pressure to scale as p ∼ N c through three orders in the hopping expansion. Such a phase differs from a hadron gas with p ∼ N 0 c , or a quark gluon plasma, p ∼ N 2 c , and was termed quarkyonic in the literature, since it shows both baryon-like and quark-like aspects. A lattice filling with baryon number shows a rapid and smooth transition from condensing baryons to a crystal of saturated quark matter, due to the Pauli principle, and is consistent with this picture. For continuum physics, the continuum limit needs to be taken before the large N c limit, which is not yet possible in practice. However, in the controlled range of lattice spacings and N c -values, our results are stable when the limits are approached in this order. We discuss possible implications for physical QCD.

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Trying to constrain the location of the QCD critical endpoint with lattice simulations

Cited by 25 publications

References 8 publications

Constraining the phase diagram of QCD at finite temperature and density

Constraining the phase diagram of QCD at finite temperature and density

Radius of convergence in lattice QCD at finite μB with rooted staggered fermions

QCD in the heavy dense regime for general Nc: on the existence of quarkyonic matter

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