arXiv subjects

C. P. Korthals Altes

Publications and source records attributed to C. P. Korthals Altes.

At least 19 recordsLinked to original sources

arXiv2009

Constrained effective potential in hot QCD

Constrained effective potentials in hot gauge theory give the probability that a configuration p of the order parameter (Polyakov loop) occurs. They are important in the analysis of surface effects and bubble formation in the plasma. The vector potential appears non-linearly in the loop; in weak coupling the linear term gives rise to the traditional free energy graphs. But the non-linear terms generate insertions of the constrained modes into the free energy graphs, through renormalisations of the Polyakov loop. These insertions are gauge dependent and are necessary to cancel the gauge dependence of the free energy graphs. The latter is shown, through the BRST identities, to have again the form of constrained mode insertions. It also follows, that absolute minima of the potential are at the centergroup values of the loop. We evaluate the two-loop contributions for SU(N) gauge theories, with and without quarks, for the full domain of the N-1 variables.

hep-th↗

arXiv2008

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.

hep-ph↗

arXiv2006

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.

hep-ph↗

arXiv2005

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.

hep-ph↗

arXiv2004

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).

hep-ph↗

arXiv2004

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 $T_c$.

hep-ph↗

arXiv2004

Quasi-particle Model in hot QCD

Magnetic quasi-particles in hot QCD predict Casimir scaling for the tension $σ$ of spatial Wilson loops. Recently this scaling has been verified on the lattice to 1--2% precision. We review how spatial loops tell us about the nature of the plasma state. The strong first order nature for more than five colours and the fast drop of the topological susceptibilty at $T_c$ found in simulations of hot quenched QCD are consistent with a quasi-particle picture valid down to the critical temperature. The magnetic quasi-particles will Bose condense in the ground state below $T_c$, and may behave like a dilute Bose gas down to T=0. The model fixes the diluteness as $σ/m_M^2$. This is a small number for all temperatures.

hep-ph↗

arXiv2003

Cosmological constraints from extra-dimension induced domain walls

TeV size extra dimensions introduce domain walls. Such walls are inconsistent with CMB anisotropies. Either inflationary dynamics washes them out, or the reheating temperature is lower then the temperature at which the walls start forming networks. As the restoration of the symmetry is non-perturbative we have performed 5d lattice simulations which show the occurrence of a cut-off in the fifth dimension as well as symmetry restoration.

hep-ph↗

arXiv2003

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.

hep-ph↗

arXiv2003

Finite temperature Z(N) phase transition with Kaluza-Klein gauge fields

If SU(N) gauge fields live in a world with a circular extra dimension, coupling there only to adjointly charged matter, the system possesses a global Z(N) symmetry. If the radius is small enough such that dimensional reduction takes place, this symmetry is spontaneously broken. It turns out that its fate at high temperatures is not easily decided with straightforward perturbation theory. Utilising non-perturbative lattice simulations, we demonstrate here that the symmetry does get restored at a certain temperature T_c, both for a 3+1 and a 4+1 dimensional world (the latter with a finite cutoff). To avoid a cosmological domain wall problem, such models would thus be allowed only if the reheating temperature after inflation is below T_c. We also comment on the robustness of this phenomenon with respect to small modifications of the model.

hep-ph↗

arXiv2001

A remark on higher dimension induced domain wall defects in our world

There has been recent interest in new types of topological defects arising in models with compact extra dimensions. We discuss in this context the old statement that if only SU(N) gauge fields and adjoint matter live in the bulk, and the coupling is weak, then the theory possesses a spontaneously broken global Z(N) symmetry, with associated domain wall defects in four dimensions. We discuss the behaviour of this symmetry at high temperatures. We argue that the symmetry gets restored, so that cosmological domain wall production could be used to constrain such models.

hep-ph↗

arXiv2001

'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.

hep-ph↗

arXiv2000

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.

hep-ph↗

arXiv1999

Phase diagram and Debye mass in thermally reduced QCD

At temperatures well above the transition, QCD admits a thermally reduced version in 3D, which reproduces the long distance physics. We analyze the phase diagram, point out the relevance of Z(3) symmetry in the location of the transition and suggest a way out to reconcile this with the data. Related to this symmetry is the existence of an observable, the Z(N) wall, or rather its 3D version, and discuss some of its advantages over other observables.

hep-lat↗

arXiv1999

The Potential for the Phase of the Wilson line at Nonzero Quark Density

The contribution of quarks to the effective potential for the phase of the Wilson line is computed at nonzero temperature and quark chemical potential to one and two loop order. At zero temperature, regardless of the value of the quark chemical potential, the effective potential for the phase of the Wilson line vanishes. At nonzero temperature, for special values of the phase the free energy of quarks equals that of bosons; at nonzero chemical potential, such quarks can ``Bose condense'', albeit with negative density.

hep-ph↗

arXiv1999

Phase diagram of 3D SU(3) gauge-adjoint Higgs system and C- violation in hot QCD

Thermally reduced QCD leads to three dimensional SU(3) gaugefields coupled to an adjoint scalar field $A_0$. We compute the effective potential in the one-loop approximation and evaluate the VEV's of $TrA_0^2$ and $TrA_0^3$. In the Higgs phase not only the former, but also the latter has a VEV. This happens where the SU(3) gauge symmetry is broken minimally with U(2) still unbroken. The VEV of the cubic invariant breaks charge conjugation and CP. It is plausible that in the Higgs phase one has a transition for large enough Higgs selfcoupling to a region where $TrA_0^3$ has no VEV and where the gaugesymmetry is broken maximally to $U(1)\times U(1)$. For a number of colours larger than 3 an even richer phase structure is possible.

hep-ph↗

arXiv1998

Phase diagram of 3D SU(3) gauge-adjoint Higgs system

Thermally reduced QCD leads to three dimensional SU(3) gaugefields coupled to an adjoint scalar field $A_0$. We compute the effective potential in the one-loop approximation and evaluate the VEV's of $TrA_0^2$ and $TrA_0^3$. In the Higgs phase not only the former, but also the latter has a VEV. This happens where the SU(3) gauge symmetry is broken minimally with U(2) still unbroken. It is plausible that in the Higgs phase one has a transition for large enough Higgs selfcoupling to a region where $TrA_0^3$ has no VEV and where the gaugesymmetry is broken maximally to $U(1)\times U(1)$.

hep-ph↗

arXiv1998

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.

hep-lat↗