Tue·Sep 3, 2002Tuesday·September 3, 2002

1. 01*

   Loop inequalities and confinement

   E.T. Tomboulis🇺🇸

   We consider correlation inequalities that follow from the well-known loop equations of LGT, and their analogues in spin systems. They provide a way of bounding long range by short or intermediate range correlations. In several cases the method easily reproduces results that otherwise require considerable effort to obtain. In particular, in the case of the 2-dimensional O(N) spin model, where large N analytical results are available, the absence of a phase transition and the exponential decay of correlations for all $\beta$ is easily demonstrated. We report on the possible application of this technique to the analogous 4-dimensional problem of area law for the Wilson loop in LGT at large $\beta$.

   hep-latNucl.Phys.B Proc.Suppl.(2003)·0 citations
2. 02*

   New Algorithm of the Finite Lattice Method for the High-temperature Expansion of the Ising Model in Three Dimensions

   Hiroaki Arisue🇯🇵 · Toshiaki Fujiwara🇯🇵

   We propose a new algorithm of the finite lattice method to generate the high-temperature series for the Ising model in three dimensions. It enables us to extend the series for the free energy of the simple cubic lattice from the previous series of 26th order to 46th order in the inverse temperature. The obtained series give the estimate of the critical exponent for the specific heat in high precision.

   hep-latcond-mat.stat-mechPhys. Rev. E 67, 066109 (2003)·4 citations
3. 03*

   Non-perturbative BRST invariance and what it might be good for

   Yigal Shamir🇮🇱 · Maarten Golterman🇺🇸

   We construct a local, gauge-fixed, lattice Yang-Mills theory with an exact BRST invariance, and with the same perturbative expansion as the standard Yang-Mills theory. The ghost sector, and some of its BRST transformation rules, are modified to get around Neuberger's theorem. A special term is introduced in the action to regularize the Gribov horizons, and the limit where the regulator is removed is discussed. We conclude with a few comments on what might be the physical significance of this theory. We speculate that there may exist new strong-interaction phases apart from the anticipated confinement phase.

   hep-latNucl.Phys.B Proc.Suppl.(2003)·1 citation
4. 04*

   Grand-Canonical simulation of 4D simplicial quantum gravity

   S. Horata🇯🇵 · H.S. Egawa🇯🇵 · T. Yukawa🇯🇵

   A thorough numerical examination for the field theory of 4D quantum gravity (QG) with a special emphasis on the conformal mode dependence has been studied. More clearly than before, we obtain the string susceptibility exponent of the partition function by using the Grand-Canonical Monte-Carlo method. Taking thorough care of the update method, the simulation is made for 4D Euclidean simplicial manifold coupled to $N_X$ scalar fields and $N_A$ U(1) gauge fields. The numerical results suggest that 4D simplicial quantum gravity (SQG) can be reached to the continuum theory of 4D QG. We discuss the significant property of 4D SQG.

   hep-latNucl.Phys.B Proc.Suppl.(2003)·8 citations
5. 05*

   Towards a strong-coupling theory of QCD at finite density

   B. Bringoltz🇮🇱 · B. Svetitsky🇮🇱

   We apply strong-coupling perturbation theory to the QCD lattice Hamiltonian. We begin with naive, nearest-neighbor fermions and subsequently break the doubling symmetry with next-nearest-neighbor terms. The effective Hamiltonian is that of an antiferromagnet with an added kinetic term for baryonic "impurities," reminiscent of the t-J model of high-T_c superconductivity. As a first step, we fix the locations of the baryons and make them static. Following analyses of the t-J model, we apply large-N methods to obtain a phase diagram in the (N_c,N_f) plane at zero temperature and baryon density. Next we study a simplified U(3) toy model, in which we add baryons to the vacuum. We use a coherent state formalism to write a path integral which we analyze with mean field theory, obtaining a phase diagram in the (n_B,T) plane.

   hep-latNucl.Phys.B Proc.Suppl.(2003)·5 citations
6. 06*

   Currents, chemical potential and boundary conditions in lattice QCD

   V.K. Mitrjushkin (JINR, Dubna)🇷🇺

   A connection between the operator fermionic currents $\text{hatJ}$ and corresponding `Grassmannian' currents $J$ in the functional integral formalism is studied. The QCD action with non--zero chemical potential $\mu$ is derived. A connection between the fermionic Fock space and boundary conditions along the forth direction is discussed.

   hep-latNucl.Phys.B Proc.Suppl.(2003)·2 citations
7. 07*

   CP breaking in lattice chiral gauge theory

   Kazuo Fujikawa🇯🇵 · Masato Ishibashi🇯🇵 · Hiroshi Suzuki🇯🇵

   The CP symmetry is not manifestly implemented for the local and doubler-free Ginsparg-Wilson operator in lattice chiral gauge theory. We precisely identify where the effects of this CP breaking appear.

   hep-latNucl.Phys.B Proc.Suppl.(2003)·4 citations
8. 08*

   Improving the Quark Number Susceptibilities for Staggered Fermions

   Rajiv V. Gavai🇮🇳

   Quark number susceptibilities approach their ideal gas limit at sufficiently high temperatures. As in the case of other thermodynamic quantities, this limit itself is altered substantially on lattices with small temporal extent, N_t = 4-8, making it thus difficult to check the validity of perturbation theory. Unlike other observables, improving susceptibilities or number densities is subject to constraints of current conservation and absence of chemical potential dependent divergences. We construct such an improved number density and susceptibility for staggered fermions and show that they approximate the continuum ideal gas limit better on small temporal lattices.

   hep-latNucl.Phys.B Proc.Suppl.(2003)·8 citations
9. 09*

   The quark mass and $\mu$ dependence of the QCD chiral critical point

   Ch. Schmidt🇩🇪 · C.R. Allton🇬🇧 · S. Ejiri🇬🇧 · S.J. Hands🇬🇧 · O. Kaczmarek🇩🇪 · F. Karsch🇩🇪 · E. Laermann🇩🇪

   In order to study the QCD chiral critical point we investigate Binder Cumulants of the chiral condensate. The results were obtained from simulations of 3 and 2+1 flavors of standard staggered fermions and 3 flavors of p4 improved staggered fermions. The quark masses used are close to the physical quark mass. To extract the dependence on quark mass and chemical potential we apply a new reweighting technique based on a Taylor expansion of the action. The reweighting accuracy is $\mathcal{O}(m)$ for the standard and $\mathcal{O}(m^2)$, $\mathcal{O}({\mu }^2)$ for the p4 action.

   hep-latNucl.Phys.B Proc.Suppl.(2003)·58 citations
10. 10*

    A Hamiltonian lattice study of the two-dimensional Wess-Zumino model

    Matteo Beccaria🇮🇹 · Massimo Campostrini🇮🇹 · Alessandra Feo🇮🇪

    We investigate a Hamiltonian lattice version of the two-dimensional Wess-Zumino model by Quantum Monte Carlo simulations. In order to study the pattern of supersymmetry breaking, we measure the ground state energy and the correlation length along a trajectory approaching the continuum limit. The algorithm is very effective in measuring the ground state energy, and adequate for the correlation length.

    hep-latNucl.Phys.B Proc.Suppl.(2003)·12 citations
11. 11*

    SO(3) Yang-Mills theory on the lattice

    A. Barresi🇩🇪 · G. Burgio🇮🇪 · M. Muller-Preussker🇩🇪

    We numerically investigate the phase structure of pure SO(3) LGT at zero and non-zero temperature in the presence of a Z2 blind monopole chemical potential. The physical meaning of the different phases, a possible symmetry breaking mechanism as well as the existence of an order parameter for the finite temperature phase transition are discussed.

    hep-latNucl.Phys.B Proc.Suppl.(2003)·16 citations
12. 12*

    The QCD phase transition at high temperature and low density

    S. Ejiri🇬🇧 · C.R. Allton🇬🇧 · S.J. Hands🇬🇧 · O. Kaczmarek🇩🇪 · F. Karsch🇩🇪 · E. Laermann🇩🇪 · Ch. Schmidt🇩🇪

    We study the thermal properties of QCD in the presence of a small quark chemical potential $\mu$. Derivatives of the phase transition point with respect to $\mu$ are computed at $\mu =0$ for 2 and 3 flavors of p-4 improved staggered fermions on a $16^3\times 4$ lattice. Moreover we contrast the case of isoscalar and isovector chemical potentials, quantify the effect of $\mu \ne 0$ on the equation of state, and comment on the screening effect by dynamical quarks and the complex phase of the fermion determinant in QCD with $\mu \ne 0$.

    hep-latNucl.Phys.B Proc.Suppl.(2003)·18 citations
13. 13*

    QCD on 2+2 anisotropic lattices

    G. Burgio🇮🇪 · A. Feo🇮🇪 · M.J. Peardon🇮🇪 · S.M. Ryan🇮🇪

    We discuss the implementation of QCD on 2+2 anisotropic lattices. Technical details regarding the choice of the action as well as perturbative and non-perturbative improvement are analyzed. The physical applications of the program are presented.

    hep-latNucl.Phys.B Proc.Suppl.(2003)·4 citations
14. 14*

    On Witten's global anomaly for higher SU(2) representations

    O. Baer

    The spectral flow of the overlap operator is computed numerically along a path connecting two gauge fields which differ by a topologically non-trivial gauge transformation. The calculation is performed for SU(2) in the 3/2 and 5/2 representation. An even-odd pattern for the spectral flow as predicted by Witten is verified. The results are, however, more complicated than naively expected.

    hep-latNucl.Phys.B Proc.Suppl.(2003)·0 citations
15. 15*

    Confining proprties of a gas of Z(2) vortices

    Srinath Cheluvaraja🇺🇸

    Vortex solutions are studied in an SO(3) gauge theory spontaneously broken to SO(2). These vortices have a Z(2) magnetic charge. A dilute gas of Z(2) vortices is studied taking into account vortex-vortex interactions. By going to a dual representation we show that odd charges are confined with a string tension which decreases exponentially with the inverse coupling.

    hep-latNucl.Phys.B Proc.Suppl.(2003)·0 citations
16. 16*

    A phase transition due to thick vortices in SU(2) lattice gauge theory

    Srinath Cheluvaraja🇺🇸

    SU(2) lattice gauge theory is studied after eliminating thin monopoles and the smallest thick monopoles. Kinematically this constraint allows thick vortex loops which produce long range Z(2) fluctuations. The thick vortex loops are identified in a three dimensional simulation. A condensate of thick vortices persists even after the thin vortices have all disappeared. They decouple at a slightly lower temperature (higher $\beta$) than the thin vortices and drive a Z(2) like phase transition.

    hep-latNucl.Phys.B Proc.Suppl.(2003)·0 citations
17. 17*

    One Loop Renormalization of Fermilab Fermions

    Matthew Nobes🇨🇦 · Howard Trottier🇨🇦

    We discuss the current status of our automatic perturbation theory program as applied to Fermilab Fermions. We give an overview of our methods, a discussion of tree level matching, and one loop results for the coefficients of the higher dimension kinetic operators.

    hep-latNucl.Phys.B Proc.Suppl.(2003)·6 citations
18. 18*

    Instantons in the nonperturbative QCD vacuum

    Nikita O. Agasian🇷🇺 · Sergei M. Fedorov🇷🇺

    The influence of nonperturbative fields on instantons in quantum chromodynamics is studied. Nonperturbative vacuum is described in terms of nonlocal gauge invariant vacuum averages of gluon field strength.Effective action for instanton is derived in bilocal approximation and it is demonstrated that stochastic background gluon fields are responsible for infra-red (IR) stabilization of instantons. Dependence of characteristic instanton size on gluon condensate and correlation length in nonperturbative vacuum is found. Comparison of obtained instanton size distribution with lattice data is made.

    ↳ hep-phhep-lathep-thPhys.Atom.Nucl.(2004)·9 citations
19. 19*

    Multi-Caloron solutions

    Falk Bruckmann🇳🇱 · Pierre van Baal🇳🇱

    We discuss the construction of multi-caloron solutions with non-trivial holonomy, both as approximate superpositions and exact self-dual solutions. The charge k SU(n) moduli space can be described by kn constituent monopoles. Exact solutions help us to understand how these constituents can be seen as independent objects, which seems not possible with the approximate superposition. An "impurity scattering" calculation provides relatively simple expressions. Like at zero temperature an explicit parametrization requires solving a quadratic ADHM constraint, achieved here for a class of axially symmetric solutions. We will discuss the properties of these exact solutions in detail, but also demonstrate that interesting results can be obtained without explicitly solving for the constraint.

    ↳ hep-thhep-latNPB(2002)·47 citations
20. 20*

    The deconfined phase near Tc and its decay into hadrons

    A. Dumitru🇺🇸 · R.D. Pisarski (Brookhaven Lab)🇺🇸

    We sketch an effective theory for the deconfined state of QCD near Tc. This relates the behavior of the expectation value of the Polyakov loop, and its two-point functions, to the pressure. Defining the ``mass'' of three and two gluon states from the imaginary and real parts of the Polyakov loop, while this ratio is 3:2 in perturbation theory, at Tc it is 3:1. We also discuss the decay of the deconfined state into hadrons.

    ↳ nucl-thhep-lathep-phnucl-exNPA(2003)·1 citation

* 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.