arXiv subjects
Publications and source records attributed to P. Giovannangeli.
The goal of this paper is two-fold. The first aim is to present a detailed version of the computation of the two-loop renormalization of the magnetic coupling in hot QCD. The second is to compare with lattice simulations the string tension of a spatial Wilson loop using the result of our two-loop computation
In this paper we provide an exact formula for the area law of the 't Hooft loop for any SU(N) gauge group to cubic order in hot gauge theory. The correction is very small for all temperatures above $T_c$, in stark contrast to the cubic correction to the pressure. The gradient approximation in a previous paper, only valid for large N, is in excellent agreement with the present, exact evalution. Comparison to lattice data is good. Casimir scaling is violated by a small amount not yet resolved by the precision of lattice data.
Spatial 't Hooft loops of strength k measure the qualitative change in the behaviour of electric colour flux in confined and deconfined phase of SU (N) gauge theory. They show an area law in the deconfined phase, known analytica lly to two loop order with a ``k-scaling'' law k(N-k). In this paper we comput e the O(g^3) correction to the tension. It is due to neutral gluon fields that get their mass through interaction with the wall. The simple k-scaling is lost in cubic order. The generic problem of non-convexity shows up in this order an d the cure is provided. The result for large N is explicitely given. We show tha t nonperturbative effects appear at O(g^5).
With the known two loop renormalisation of the magnetic coupling, the 4D results of the spatial Wilson loop are compared to the prediction from the magnetostatic sector.
Well above the critical temperature hot QCD is described by 3d electrostatic QCD with gauge coupling $g_E$ and Debye mass $m_E$. We integrate out the Debye scales to two loop accuracy and find for the gauge coupling in the resulting magnetostatic action $g_M^2=g_E^2(1-{1\over{48}}{g_E^2N\over{πm_E}} -{17\over{4608}}({g_E^2N\over{πm_E}})^2+O(({g_E^2N\over{πm_E}})^3))$.
Spatial 't Hooft loops of strength k measure the qualitative change in the behaviour of electric colour flux in confined and deconfined phase of SU(N) gauge theory. They show an area law in the deconfined phase, known analytically to two loop order with a ``k-scaling'' law k(N-k). In this paper we compute the O(g^3) correction to the tension. It is due to neutral gluon fields that get their mass through interaction with the wall. The simple k-scaling is lost in cubic order. The generic problem of non-convexity shows up in this order. The result for large N is explicitely given.
We show at very high temperature how the behaviour of the spatial 't Hooft loop in the QCD plasma is simply related to the chromo electric flux of the gluons. This simple picture is vindicated by a systematic quasi classical approach. The spatial Wilson loop 's behaviour is computed by a similar nearly free plasma of magnetic quasiparticles. This model predicts unambiguously ratios of multiply charged Wilson loops. Recent simulations confirm these predictions accurately.
The spatial 't Hooft loop measuring the electric flux and the spatial Wilsonloop measuring the magnetic flux are analyzed in hot SU(N) gauge theory. Both display area laws. On one hand the tension of the 't Hooft loop is perturbatively calculable, in the same sense as the pressure. We show that the O(g^3) contribution is absent. The ratio of multi-charged 't Hooft loops have a remarkably simple dependence on the charge, true up to, but not including, O(g^4). This dependence follows also from a simple model of free screened colour charges. On the other hand the surface tension of the Wilsonloop is non-perturbative. But in a model of screened free monopoles at very high temperature the known area law follows. The density of these monopoles starts to contribute to O(g^6) to the pressure. The ratio of the multicharged Wilson loops is calculable and identical to that of the 't Hooft loops.