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

Cubic order for spatial 't Hooft loop 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 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.Comment: 5 pages, appears in the proceedings of SEWM200

Spatial 't Hooft loop to cubic order in hot QCD II

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.Comment: 21 pages, 5 figures, submitted to Nucl. Phys. B. Minor changes mad

Interfaces in hot gauge theory

The string tension at low T and the free energy of domain walls at high T can be computed from one and the same observable. We show by explicit calculation that domain walls in hot Z(2) gauge theory have good thermodynamical behaviour. This is due to roughening of the wall, which expresses the restoration of translational symmetry.Comment: Contributed paper to the proceedings of the second workshop on Continuous Advances in QCD, ITP, University of Minnesota, Minneapolis, Minnesota, USA, March 28-31, 1996. 11 pages, figures and style file are appended in uuencoded gzip.tar.fil

Magnetic Z(N) symmetry in hot QCD and the spatial Wilson loop

We discuss the relation between the deconfining phase transition in gauge theories and the realization of the magnetic Z(N) symmetry. At low temperature the Z(N) symmetry is spontaneously broken while above the phase transition it is restored. This is intimately related to the change of behaviour of the spatial 't Hooft loop discussed in hep-ph/9909516. We also point out that the realization of the magnetic symmetry has bearing on the behaviour of the spatial Wilson loop. We give a physical argument to the effect that at zero temperature the spatial Wilson loop must have perimeter law behaviour in the symmetric phase but area law behaviour in the spontaneously broken phase. At high temperature the argument does not hold and the restoration of magnetic Z(N) is consistent with area law for the Wilson loop.Comment: 30 pages, discussion of the Wilson loop at high temperature completely revised, new references adde