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

Scalar Field Dynamics: Classical, Quantum and in Between

Using a Hartree ensemble approximation, we investigate the dynamics of the \f^4 model in 1+1 dimensions. We find that the fields initially thermalize with a Bose-Einstein distribution for the fields. Gradually, however, the distribution changes towards classical equipartition. Using suitable initial conditions quantum thermalization is achieved much faster than the onset of this undesirable equipartition. We also show how the numerical efficiency of our method can be significantly improved.Comment: Presented at SEWM 2000, 6 pages including figures, reference correcte

Twin Peaks

The on-shell imaginary part of the retarded selfenergy of massive \vr^4 theory in 1+1 dimensions is logarithmically infrared divergent. This leads to a zero in the spectral function, separating its usual bump into two. The twin peaks interfere in time-dependent correlation functions, which causes oscillating modulations on top of exponential-like decay, while the usual formulas for the decay rate fail. We see similar modulations in our numerical results for a mean field correlator, using a Hartree ensemble approximation.Comment: Presented at SEWM 2000, language correction

Quasi particles in hot QCD

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.Comment: 3 pages. Talk given at Lattice200

Gauge Theories with a Layered Phase

We study abelian gauge theories with anisotropic couplings in $4+D$ dimensions. A layered phase is present, in the absence as well as in the presence of fermions. A line of second order transitions separates the layered from the Coulomb phase, if $D\leq 3$.Comment: 17 pages+9 figures (in LATeX and PostScript in a uuencoded, compressed tar file appended at the end of the LATeX file) , CPT-94/P.303

ZQCD and universal matching to domain walls

We discuss the one loop matching procedure in ZQCD. Universality and Casimir scaling leave -in terms of the 't Hooft coupling- just two combinationsof parameters to be fixed numerically. These numbers are then the same for any number of colours.Comment: submitted to proceeding of Strong and Electroweak Matter 2008, Amsterda

't Hooft and Wilson loop ratios in the QCD plasma

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.Comment: 28 pages, 8 figure

Debye mass from domainwalls and dimensionally reduced phase diagram

To measure the Debye mass in dimensionally reduced QCD for $N_c\le 3$ we replace in the correlator of two Polyakov loops one of the loops by a wall triggered by a dimensionally reduced twist. The phase diagram for $N_c=3$ has R-parity broken in part of the Higgs phase.Comment: LATTICE98(hightemp

Chiral Defect Fermions and the Layered Phase

Chiral defect fermions on the lattice in 4+1 dimensions are analyzed using mean field theory. The fermion propagator has a localized chiral mode in weak coupling but loses it when the coupling in the unphysical fifth direction becomes too large. A layered phase \`a la Fu-Nielsen appears where the theory is vector-like in every layer.Comment: 9 pages + postscript figure (We have correctly quoted the work of our reference 10 in the paper

Properties of the deconfining phase transition in SU(N) gauge theories

We extend our earlier investigation of the finite temperature deconfinement transition in SU(N) gauge theories, with the emphasis on what happens as N->oo. We calculate the latent heat in the continuum limit, and find the expected quadratic in N behaviour at large N. We confirm that the phase transition, which is second order for SU(2) and weakly first order for SU(3), becomes robustly first order for N>3 and strengthens as N increases. As an aside, we explain why the SU(2) specific heat shows no sign of any peak as T is varied across what is supposedly a second order phase transition. We calculate the effective string tension and electric gluon masses at T=Tc confirming the discontinuous nature of the transition for N>2. We explicitly show that the large-N `spatial' string tension does not vary with T for T<Tc and that it is discontinuous at T=Tc. For T>Tc it increases as T-squared to a good approximation, and the k-string tension ratios closely satisfy Casimir Scaling. Within very small errors, we find a single Tc at which all the k-strings deconfine, i.e. a step-by-step breaking of the relevant centre symmetry does not occur. We calculate the interface tension but are unable to distinguish between linear or quadratic in N variations, each of which can lead to a striking but different N=oo deconfinement scenario. We remark on the location of the bulk phase transition, which bounds the range of our large-N calculations on the strong coupling side, and within whose hysteresis some of our larger-N calculations are performed.Comment: 50 pages, 14 figure