Dilute monopole gas, magnetic screening and k-tensions in hot gluodynamics

An adjoint multiplet of screened monopoles forming a dilute gas fits very well lattice data at high $T$. There are now seven ratios for k-strings available, checking within a few percent with the prediction $k(N-k)$. The diluteness turns out to be a small parameter for SU(N) gluodynamics, to a good approximation ($1\over N^2$) independent of the value of $N$, and also independent of $T$. This suggests a dilute Bose-Einstein gas, with a BE transition at the deconfinement temperature $T_c$.Comment: 13 pages, talk given at Workshop on Continuous Advances in QCD 2004, Minneapolis, Minnesota, 13-16 May 200

Magnetic monopoles in hot QCD

In this talk we review how a dilute gas of magnetic monopoles in the adjoint describes the spatial k-Wilson loops. We formulate an effective theory from $S_{MQCD}$ by integrating out dof's down to scales in between the magnetic screening mass and the string tension and relate the 3d pressure and the string tension. Lattice data are consistent with the gas being dilute for all temperatures.Comment: 7 pages, two figures, talk given at Continuous Advances in QCD, Minneapolis, May 200

Effective potential analysis for 5D SU(2) gauge theories at finite temperature and radius

We calculate the one loop effective potential for a 5D SU(2) gauge field theory at finite temperature $T=1/\beta$ and radius R=1/M. This calculation is performed, for the first time, in the case of background fields with two constant components $A^{3}_{y}$ (directed towards the compact extra dimension with radius R) and $A^{3}_{\tau}$ (directed towards the compact Euclidean time with radius $\beta$). This model possesses two discrete symmetries known as Z_{M}(2) and Z_{T}(2). The corresponding phase diagram is presented in Ref. 4. However the arguments which lead to this diagram are mainly qualitative. We present a detailed analysis, from our point of view, for this phase diagram, and we support our arguments performing lattice simulations for a simple phenomenological model with two scalar fields interacting through the previously calculated potential.Comment: 18 pages, 7 figures ; typos correcte

Spatial 't Hooft loop to cubic order in hot QCD

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).Comment: 22 pages. Apart from a discussion on the renormalization effect of the Polyakov loop to cubic order only cosmetic changes with respect to the earlier hep-ph/021229