相关论文: A test of Taylor- and modified Taylor-expansion
Series expansions in the chemical potential mu are studied for an effective theory of QCD which has a flux representation where the complex action is overcome. In particular we consider fugacity series, Taylor expansion and a modified…
Using the effective center model of QCD we test series expansions for finite chemical potential $\mu$. In particular we study two variants of Taylor expansion as well as the fugacity series. The effective center model has a dual…
We investigate the reliability of the Taylor expansion method in QCD with isospin chemical potentials using lattice simulations. By comparing the expansion of the number density to direct results, the range of validity of the leading- and…
Properties of QCD at finite chemical potential are extracted using Taylor series expansions. The continuum limits of lattice results are presented. The result of expanding the free energy density, ie, the pressure, to 6th order in the…
We present results on the QCD equation of state, obtained with two different improved dynamical staggered fermion actions and almost physical quark masses. Lattice cut-off effects are discussed in detail as results for three different…
Convergence properties of Taylor expansions of observables, which are also used in lattice QCD calculations at non-zero chemical potential, are analyzed in an effective N_f = 2+1 flavor Polyakov-quark-meson model. A recently developed…
We discuss the Taylor expansion approach to non-zero baryon chemical potential ($\mu_B$) and present results on expanion coefficients of the pressure and energy density up to the 6-th order in $\mu_B$. Calculations have been performed with…
We discuss the phase structure and the equation of state for QCD at non-zero temperature and density. Derivatives of $\ln Z$ with respect to quark chemical potential $\mu_q$ up to fourth order are calculated for 2-flavor QCD, enabling…
I give an elementary introduction to the study of gauge theories coupled to fermions with many degrees of freedom. Besides their intrinsic interest, these theories are candidates for nonperturbative extensions of the Higgs sector of the…
For theories plagued with a sign problem at finite density, a Taylor expansion in the chemical potential is frequently used for lattice gauge theory based computations of the equation of state. Recently, in arXiv:2106.03165, a new…
We study the existence of formal Taylor expansions for functions defined on fields of generalised series. We prove a general result for the existence and convergence of those expansions for fields equipped with a derivation and an…
We investigate the possibility of coupling a chemical potential only to the physical chiral fermions on the lattice starting from the many body state description of overlap fermions. After developing the formalism for a chiral gauge theory,…
We analyze general convergence properties of the Taylor expansion of observables to finite chemical potential in the framework of an effective 2+1 flavor Polyakov-quark-meson model. To compute the required higher order coefficients a novel…
Convergence of three different expansion schemes at finite baryon chemical potentials, including the conventional Taylor expansion, the Pad\'e approximants, and the $T'$ expansion proposed recently in lattice QCD simulations, have been…
We study the linear response to an external electric field of a system of fermions in a lattice at zero temperature. This allows to measure numerically the Euclidean conductivity which turns out to be compatible with an analytical…
We study QCD with 2+1 flavors at nonzero temperature and nonzero chemical potential. We present preliminary results obtained from lattice calculations performed with an improved staggered fermions action (p4-action) on lattice with temporal…
We perform the first direct determination of the position of the leading singularity of the pressure in the complex chemical potential $\mu_B$ plane in lattice QCD using numerical simulations with 2-stout improved rooted staggered fermions.…
Lattice gauge theories are a powerful language to theoretically describe a variety of strongly correlated systems, including frustrated magnets, high-$T_c$ superconductors, and topological phases. However, in many cases gauge fields couple…
We present preliminary results for the curvature of the pseudocritical line and susceptibilities in Nf = 2 + 1 flavor QCD. The computations are carried out on lattice sizes of 16x16x16x4, at matching parameters of early work of the…
We present results on the QCD equation of state, obtained with two different improved dynamical staggered fermion actions and almost physical quark masses. Lattice cut-off effect are discussed in detail as results for three different…