Chiral phase transition at finite chemical potential in 2+1 -flavor soft-wall anti–de Sitter space QCD

Abstract

The phase transition from hadronic matter to chirally-symmetric quarkgluon plasma is expected to be a rapid crossover at zero quark chemical potential (µ), becoming first order at some finite value of µ, indicating the presence of a critical point. Using a three-flavor soft-wall model of AdS/QCD, we investigate the effect of varying the light and strange quark masses on the order of the chiral phase transition. At zero quark chemical potential, we reproduce the Columbia Plot, which summarizes the results of lattice QCD and other holographic models. We then extend this holographic model to examine the effects of finite quark chemical potential. We find that the the chemical potential does not affect the critical line that separates first-order from rapid crossover transitions. This excludes the possibility of a critical point in this model, suggesting that a different setup is necessary to reproduce all the features of the QCD phase diagram.

Pion condensation in a soft-wall AdS/QCD model

“…In this case, one can check S a , π b , η vanish if there are no extra source of the corresponding operator. The phase structure in this situation has been studied in [52][53][54][55][56][57][58][59][60][61][62][63][64] . In this work, since we would like to discuss the effects of isospin chemical potential on phase transition, we have to take non-vanishing V M , A M .…”

“…Its extended models [39][40][41][42][43][44][45][46][47][48][49][50][51] could predict meson spectra in good agreement with experimental data. It is also easy to be extended to finite temperature and give good description of chiral phase transition [52][53][54][55][56][57][58][59][60][61][62][63][64] (see also other bottom-up holographic models [65][66][67][68][69][70]). Thus, we will follow the idea of [34] and introduce temperature T and isospin chemical potential µ I in soft-wall model.…”

Quarkyonic phase from quenched dynamical holographic QCD model

“…The deconfinement phase transition has been widely discussed with the expectation value of Polyakov loop as the order parameter of deconfinement phase transition. However, till recently, the dynamical spontaneous chiral symmetry breaking and chiral phase transition have been realized in soft-wall holographic QCD model [99][100][101][102][103][104][105][106][107][108][109][110][111][112][113][114][115][116] with the chiral condensate as the order parameter.…”

Chiral phase transition and QCD phase diagram from AdS/QCD

“…As shown in our previous work [68], the improved soft-wall model with a z-dependent bulk scalar mass and a quartic scalar-coupling term can realize consistently the properties of linear confinement and spontaneous chiral symmetry breaking. In the 2 + 1 flavor case, several studies have shown that the flavor-mixing effect introduced by a 't Hooft determinant term of the bulk scalar field is necessary for the correct realization of chiral phase transition [112][113][114]. Our recent work shows that the improved soft-wall model with the determinant term added can reproduce the expected quark-mass dependence of the order of chiral phase transition [113].…”

“…The original soft-wall model is too simple to realize the correct chiral transition behavior [110]. One can refer to [111,112] for similar considerations in another modified soft-wall model, where no CEP shows in their calcultion. From the above study, we see that the chiral phase transition at physical quark mass in our improved soft-wall model contains naturally a CEP linking the crossover transition at smaller µ with the first-order phase transition at larger µ.…”