اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدA study of the sign problem for lattice QCD with chemical potential
137
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
We study the expectation value of the phase of the fermion determinant for Wilson lattice fermions with chemical potential. We use quenched SU(3) ensembles and implement a recently proposed exact dimensional reduction of the fermion determinant. Ensembles at several temperatures below and above the phase transition are studied and we analyze the role of the quark mass, the temperature, the volume and the topological sectors. We compare our numerical results to predictions from chiral perturbation theory.
قيم البحث
اقرأ أيضاً
We provide the most accurate results for the QCD transition line so far. We optimize the definition of the crossover temperature $T_c$, allowing for its very precise determination, and extrapolate from imaginary chemical potential up to real $mu_B ap
prox 300$ MeV. The definition of $T_c$ adopted in this work is based on the observation that the chiral susceptibility as a function of the condensate is an almost universal curve at zero and imaganiary $mu_B$. We obtain the parameters $kappa_2=0.0153(18)$ and $kappa_4=0.00032(67)$ as a continuum extrapolation based on $N_t=10,12$ and $16$ lattices with physical quark masses. We also extrapolate the peak value of the chiral susceptibility and the width of the chiral transition along the crossover line. In fact, both of these are consistent with a constant function of $mu_B$. We see no sign of criticality in the explored range.
We compare higher moments of baryon numbers measured at the RHIC heavy ion collision experiments with those by the lattice QCD calculations. We employ the canonical approach, in which we can access the real chemical potential regions avoiding the sig
n problem. In the lattice QCD simulations, we study several fits of the number density in the pure imaginary chemical potential, and analyze how these fits affects behaviors at the real chemical potential. In the energy regions between $sqrt{s}_{NN}$=19.6 and 200 GeV, the susceptibility calculated at $T/T_c=0.93$ is consistent with experimental data at $0 le mu_B/T < 1.5$, while the kurtosis shows similar behavior with that of the experimental data in the small $mu_B/T$ regions $0 le mu_B/T < 0.3$. The experimental data at $sqrt{s}_{NN}=$ 11.5 shows quite different behavior. The lattice result in the deconfinement region,$T/T_c=1.35$, is far from experimental data.
We study the heavy-heavy-light quark ($QQq$) potential in SU(3) quenched lattice QCD, and discuss one of the roles of the finite-mass valence quark in the inter-quark potential. Monte Carlo simulations are performed with the standard gauge action on
the $16^4$ lattice at $beta =6.0$ and the $O(a)$-improved Wilson fermion action at four hopping parameters. For statistical improvement, the gauge configuration is fixed with the Coulomb gauge. We calculate the potential energy of $QQq$ systems as a function of the inter-heavy-quark distance $R$ in the range of $R le$ 0.8 fm. The $QQq$ potential is well described with a Coulomb plus linear potential, and the effective string tension between the two heavy quarks is significantly smaller than the string tension $sigma simeq 0.89$ GeV/fm. It would generally hold that the effect of the finite-mass valence quark reduces the inter-two-quark confinement force in baryons.
The path optimization has been proposed to weaken the sign problem which appears in some field theories such as finite density QCD. In this method, we optimize the integration path in complex plain to enhance the average phase factor. In this study,
we discuss the application of this method to low dimensional QCD as a first step of finite density QCD.
The phase diagram of two-color QCD with a chiral chemical potential is studied on the lattice. The focus is on the confinement/deconfinement phase transition and the breaking/restoration of chiral symmetry. The simulations are carried out with dynami
cal staggered fermions without rooting. The dependence of the Polyakov loop, the chiral condensate and the corresponding susceptibilities on the chiral chemical potential and the temperature are presented.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
