论文标题
有限密度SU中的电导率（2）带有动力费用的晶格量表理论
Electric conductivity in finite-density SU(2) lattice gauge theory with dynamical fermions
论文作者
论文摘要
我们研究了电导率对有限密度的化学电位的依赖性$ su（2）$ gauge理论，$ n_f = 2 $扎根交错的海夸克的风味，以及威尔逊 - 迪拉克和域壁瓦克夸克。 Pion质量相当小，$M_π/M_ρ\约0.4 $。我们特别集中在手性跨界的附近，在那里我们发现低频电导率对费米度密度的小变化最敏感。在低密度QCD状态下以自发损坏的手性对称性工作，我们获得了电导率扩展$σ（t，μ）=σ（t，0）\ left（t，t）（1 + c（1 + c（t）（μ/t）^2 + O（μ/t）$ firevion pow的电导率$σ（t，t，0）$的第一个非繁琐系数$ c（t）$ in $ c（t，t，0）并将其最大值$ c（t）\大约0.10 \ pm 0.07 $在临界温度周围。在较大的密度和较低的温度下，电导率迅速朝着diquark凝结阶段生长，并且也更接近自由夸克结果。作为我们研究的副产品，我们证实了先前的研究的结论，即较重的触发，对于$ su（2）$量表理论，交叉温度与茶质量$ t_c/m_π\ t_c/m_π\约0.4 $ at $μ= 0 $的比率明显小于实际QCD。
We study the dependence of the electric conductivity on chemical potential in finite-density $SU(2)$ gauge theory with $N_f = 2$ flavours of rooted staggered sea quarks, in combination with Wilson-Dirac and Domain Wall valence quarks. The pion mass is reasonably small with $m_π/m_ρ \approx 0.4$. We concentrate in particular on the vicinity of the chiral crossover, where we find the low-frequency electric conductivity to be most sensitive to small changes in fermion density. Working in the low-density QCD-like regime with spontaneously broken chiral symmetry, we obtain an estimate of the first nontrivial coefficient $c(T)$ of the expansion of conductivity $σ(T,μ) = σ(T,0) \left(1 + c(T) (μ/T)^2 + O(μ^4)\right)$ in powers of $μ$, which has rather weak temperature dependence and takes its maximal value $c(T) \approx 0.10 \pm 0.07$ around the critical temperature. At larger densities and lower temperatures, the conductivity quickly grows towards the diquark condensation phase, and also becomes closer to the free quark result. As a by-product of our study we confirm the conclusions of previous studies with heavier pion that for $SU(2)$ gauge theory the ratio of crossover temperature to pion mass $T_c/m_π \approx 0.4$ at $μ=0$ is significantly smaller than in real QCD.
