479 research outputs found
Gauge copies in the Landau-DeWitt gauge : a background invariant restriction
The Landau background gauge, also known as the Landau-DeWitt gauge, has found renewed interest during the past decade given its usefulness in accessing the confinement-deconfinement transition via the vacuum expectation value of the Polyakov loop, describable via an appropriate background. In this Letter, we revisit this gauge from the viewpoint of it displaying gauge (Gribov) copies. We generalize the Gribov-Zwanziger effective action in a BRST and background invariant way; this action leads to a restriction on the allowed gauge fluctuations, thereby eliminating the infinitesimal background gauge copies. The explicit background invariance of our action is in contrast with earlier attempts to write down and use an effective Gribov-Zwanziger action. It allows to address certain subtleties arising in these earlier works, such as a spontaneous and thus spurious Lorentz symmetry breaking, something which is now averted
The asymmetry of the dimension two condensate
I present recent analytical work concerning the electric-magnetic asymmetry
in the dimension two condensate in pure Yang-Mills theory. We reproduce
qualitatively the lattice results previously found by Chernodub and Ilgenfritz.Comment: poster presented by David Vercauteren at Light Cone 2010, June 14-18,
2010, Valencia, Spai
BRST invariant condensates in Gribov-Zwanziger theory
In this proceeding, Yang-Mills theory is quantized in the linear
covariant gauges, while taking into account the issue of Gribov copies and we
construct the one-loop effective potential for a set of mass dimension 2
condensates, including the Gribov parameter, that refines the infrared region
of the Gribov-Zwanziger theory, whilst respecting renormalization group
invariance and BRST symmetry
SU(2) x U(1) Yang-Mills theories in 3d with Higgs field and Gribov ambiguity
We study the structure of the gauge propagators of a 3d version of the electroweak interaction in terms of the Higgs vacuum expectation value., of the non-Abelian gauge coupling g, and of the Abelian gauge coupling g', when nonperturbative effects related to the non-Abelian gauge fixing are introduced by means of an adapted path integral measure. In the perturbative regime of small nonAbelian coupling g and sufficiently large, nu the well-known standard Z and W propagators are recovered, together with a massless photon. In general, depending on the relative magnitudes of g, g' and., we uncover a quite different propagator structure. In a later stage of research, the results here derived can be used to study the associated phase diagram in more depth
Invasive Wild pigs as primary nest predators for Wild turkeys
Depredation of wild turkey (Meleagris gallopavo) nests is a leading cause of reduced recruitment for the recovering and iconic game species. invasive wild pigs (Sus scrofa) are known to depredate nests, and have been expanding throughout the distributed range of wild turkeys in north America. We sought to gain better insight on the magnitude of wild pigs depredating wild turkey nests. We constructed simulated wild turkey nests throughout the home ranges of 20 GPS-collared wild pigs to evaluate nest depredation relative to three periods within the nesting season (i.e., early, peak, and late) and two nest densities (moderate = 12.5-25 nests/km2, high = 25-50 nests/km2) in south-central Texas, USA during March–June 2016. Overall, the estimated probability of nest depredation by wild pigs was 0.3, equivalent to native species of nest predators in the study area (e.g., gray fox [Urocyon cinereoargenteus], raccoon [Procyon lotor], and coyote [Canis latrans]). female wild pigs exhibited a constant rate of depredation regardless of nesting period or density of nests. However, male wild pigs increased their rate of depredation in areas with higher nest densities. Management efforts should remove wild pigs to reduce nest failure in wild turkey populations especially where recruitment is low
Analytic approach to the study of the electric magnetic asymmetry of the dimension-2 condensate
Recent work by Chernodub and Ilgenfritz has uncovered nontrivial temperature dependence in the electric magnetic asymmetry in the dimension-2 condensate. This asymmetry measures the difference between the spatial and the temporal components of the condensate. Lattice computations have shown very interesting phenomena. The asymmetry shows a jump at the deconfinement phase transition, beyond which it approaches its perturbative value. At temperatures lower than the critical temperature, it shows an exponential behavior with a mass in the exponent smaller than the lowest glueball mass. In this talk we present the research done on this asymmetry, using a generalization of analytical methods developed to study . The purpose is to shed more insight on the findings of Chernodub and Ilgenfritz
Semiclassical analysis of the phases of 4d SU(2) Higgs gauge systems with cutoff at the Gribov horizon
We present an analytical study of continuum 4d SU(2) gauge-Higgs models with a single Higgs field with fixed length in either the fundamental or adjoint representation. We aim at analytically probing the renowned predictions of Fradkin and Shenker on the phase diagram in terms of confinement versus Higgs behavior, obtained for the lattice version of the model. We work in the Landau version of the ' t Hooft R xi gauges in which case we can access potential nonperturbative physics related to the existence of the Gribov copies. In the fundamental case, we clearly show that in the perturbative regime of small gauge coupling constant g and large Higgs vacuum expectation value (vev) nu, there is a Higgs phase with Yukawa gauge boson propagators without Gribov effects. For a small value of the Higgs vev nu and/or large g, we enter a region with Gribov-type propagators that have no physical particle interpretation: the gauge bosons are as such confined. The transition between both behaviors is found to be continuous. In the adjoint case, we find evidence of a more drastic transition between the different behaviors for the propagator of the off- diagonal gauge bosons, whereas the "photon,'' i.e. the diagonal component of the gauge field, displays a propagator of the Gribov-type. In the limit of infinite Higgs condensate, we show that a massless photon is recovered. We compare our findings with those of Fradkin and Shenker as well as with more recent numerical lattice simulations of the fundamental Higgs model. We also carefully discuss in which region of the parameter space (nu, g) our approximations are trustworthy
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