Fluctuations in the quark-meson model for QCD with isospin chemical potential
Fluctuations in the quark-meson model for QCD with isospin chemical potential
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DOI：
10.1016/j.physletb.2012.11.055
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发表时间：
2012-07
影响因子：
4.4
通讯作者：
Kazuhiko Kamikado;N. Strodthoff;L. Smekal;J. Wambach
中科院分区：
文献类型：
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作者：
Kazuhiko Kamikado;N. Strodthoff;L. Smekal;J. Wambach
本文研究了具有泛函重整化群（FRG）的双味夸克-介子（QM）模型在有限重子和同位旋化学势μ和μI下集体介子涨落对QCD相图的影响.在只有同位旋化学势的情况下，在有限重子化学势下，双色QCD的夸克-介子-双夸克模型中，手征凝聚与π凝聚的竞争动力学与介子和重子集体涨落的竞争动力学之间存在精确的等价性。然而，与双色QCD相比，有限μB=3μ在相图中引入了额外的维度。在零温度下，该相图的（μI，μ）平面受到“银焰问题”的强烈约束。特别是，只要μ+μ I低于QM模型的组分夸克质量或QCD中核物质的液-气跃迁线，π凝聚的开始就必须发生在μI=mπ/2处，与μ无关。为了在平均场之外保持这种关系，关键是以一致的方式从它的类时相关器与FRG计算π介子质量。
We study the two-flavor quark-meson (QM) model with the functional renormalization group (FRG) to describe the effects of collective mesonic fluctuations on the phase diagram of QCD at finite baryon and isospin chemical potentials, μBand μI. With only isospin chemical potential there is a precise equivalence between the competing dynamics of chiral versus pion condensation and that of collective mesonic and baryonic fluctuations in the quark-meson-diquark model for two-color QCD at finite baryon chemical potential. Here, finite μB=3μ introduces an additional dimension to the phase diagram as compared to two-color QCD, however. At zero temperature, the (μI,μ) plane of this phase diagram is strongly constrained by the “Silver Blaze problem.” In particular, the onset of pion condensation must occur at μI=mπ/2, independent of μ as long as μ+μIstays below the constituent quark mass of the QM model or the liquid-gas transition line of nuclear matter in QCD. In order to maintain this relation beyond mean field it is crucial to compute the pion mass from its timelike correlator with the FRG in a consistent way.