Mon·Oct 13, 2003Monday·October 13, 2003

1. 01*

   A Novel Ansatz for the Energy-Momentum Tensor on the Lattice

   Joachim Holk (Heidelberg U.)🇩🇪

   The comparison of structural analogies between the energy-momentum tensors in general relativity and in a gauge theory of Yang-Mills type is tentatively extended to lattice physics. These considerations are guiding to a new lattice model for the symmetric energy-momentum tensor ${\Theta }_{\mu \nu }$ of the pure Yang-Mills gauge sector, basing on half powers of the plaquette variable. The concept of non-trivial principal square roots of unitary matrices in lattice gauge theories can be epitomized to reconcile the pretension to a uniform construction principle for the components of ${\Theta }_{\mu \nu }$ with general qualitative thermodynamic demands concerning arguments in favour of a Wilson form for $<{\Theta }_{\mu }^{\mu }>$ and ${\Theta }_{44}$. SU(2) Monte Carlo results for the Euclidean expectation values on a 10**4 lattice are compared with that of competing hitherto existing lattice models for ${\Theta }_{\mu \nu }$.

   hep-lat0 citations
2. 02*

   Spontaneous symmetry breaking in strong-coupling lattice QCD at high density

   Barak Bringoltz🇮🇱 · Benjamin Svetitsky (Tel Aviv University)🇮🇱

   We determine the patterns of spontaneous symmetry breaking in strong-coupling lattice QCD in a fixed background baryon density. We employ a next-nearest-neighbor fermion formulation that possesses the SU(N_f)xSU(N_f) chiral symmetry of the continuum theory. We find that the global symmetry of the ground state varies with N_f and with the background baryon density. In all cases the condensate breaks the discrete rotational symmetry of the lattice as well as part of the chiral symmetry group.

   hep-latPRD(2004)·11 citations
3. 03*

   QCD phenomenology of static sources and gluonic excitations at short distances

   Gunnar S. Bali (Glasgow)🇬🇧 · Antonio Pineda (Barcelona)🇪🇸

   New lattice data for the Pi_u and Sigma_u^- potentials at short distances are presented. We compare perturbation theory to the lower static hybrid potentials and find good agreement at short distances, once the renormalon ambiguities are accounted for. We use the non-perturbatively determined continuum-limit static hybrid and ground state potentials at short distances to determine the gluelump energies. The result is consistent with an estimate obtained from the gluelump data at finite lattice spacings. For the lightest gluelump, we obtain Lambda_B^{RS}(nu_f=2.5/r_0)=[2.25\pm 0.10(latt.)\pm 0.21 (th.)\pm 0.08 (Lambda_{MS})]/r_0 in the quenched approximation with r_0^{-1} approx 400 MeV. We show that, to quote sensible numbers for the absolute values of the gluelump energies, it is necessary to handle the singularities of the singlet and octet potentials in the Borel plane. We propose to subtract the renormalons of the short-distance matching coefficients, the potentials in this case. For the singlet potential the leading renormalon is already known and related to that of the pole mass, for the octet potential a new renormalon appears, which we approximately evaluate. We also apply our methods to heavy light mesons in the static limit and from the lattice simulations available in the literature we obtain the quenched result \bar{Lambda}^{RS}(nu_f=2.5/r_0)=[1.17\pm 0.08(latt.)\pm 0.13 (th.) \pm 0.09 (Lambda_{MS})]/r_0. We calculate m_{b,MS}(m_{b,MS}) and apply our methods to gluinonia whose dynamics are governed by the singlet potential between adjoint sources. We can exclude non-standard linear short-distance contributions to the static potentials, with good accuracy.

   ↳ hep-phhep-lathep-thPRD(2004)·178 citations
4. 04*

   Is there a linear potential at short distances?

   Antonio Pineda🇪🇸

   We argue that the lattice data of the static potential can be explained by perturbation theory up to energies of the order of 1 GeV once renormalons effects are taken into account

   ↳ hep-phhep-lathep-thNucl.Phys.B Proc.Suppl.(2004)·9 citations
5. 05*

   Compact U(1) gauge theories in 2+1 dimensions and the physics of low dimensional insulating materials

   F. S. Nogueira🇩🇪 · J. Smiseth🇳🇴 · E. Smoergrav🇳🇴 · A. Sudbo🇳🇴

   Compact abelian gauge theories in $d=2+1$ dimensions arise often as an effective field-theoretic description of models of quantum insulators. In this paper we review some recent results about the compact abelian Higgs model in $d=2+1$ in that context.

   ↳ hep-thcond-mathep-latEPJC(2004)·11 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.