Probing Confinement with Chromomagnetic Fields

Using the lattice Schr\"odinger functional we study vacuum dynamics of SU(3) gauge theory at finite temperature. The vacuum is probed by means of an external constant Abelian chromomagnetic field. We find that by increasing the strength of the applied external field the deconfinement temperature decreases towards zero. This implies that strong enough Abelian chromomagnetic fields destroy confinement of color.Comment: Lattice2002(topology). 3 pages, 3 figure

Exploring the Dynamics of Three-Dimensional Lattice Gauge Theories by External Fields

We investigate the dynamics of three-dimensional lattice gauge theories by means of an external Abelian magnetic field. For the SU(2) lattice gauge theory we find evidence of the unstable modes.Comment: 3 pages, PostScript. Contribution to the LATTICE 93 Conference (Dallas, U.S.A., September 1993) preprint BARI-TH-162/9

Investigations on the deconfining phase transition in QCD

We investigate the deconfining phase transition in SU(3) pure gauge theory and in full QCD with two flavors of staggered fermions by means of a gauge invariant thermal partition functional. In the pure gauge case our finite size scaling analysis is in agreement with the well known weak first order phase transition. In the case of 2 flavors full QCD we find that the phase transition is consistent with weak first order, contrary to the expectation of a crossover for not too large quark masses.Comment: 3 pages, 3 figures, Lattice2003(topology

Unstable Modes and Confinement in the Lattice Schr\"odinger Functional Approach

We analyze the problem of the Nielsen-Olesen unstable modes in the SU(2) lattice gauge theory by means of a recently introduced gauge-invariant effective action. We perform numerical simulations in the case of a constant Abelian chromomagnetic field. We find that for lattice sizes above a certain critical length the density of effective action shows a behaviour compatible with the presence of the unstable modes. We put out a possible relation between the dynamics of the unstable modes and the confinement.Comment: 15 pages, LaTeX2e file, 5 figure

No Primordial Magnetic Field from Domain Walls

It is pointed out that, contrary to some claims in the literature, the domain walls cannot be a source of a correlated at large scales primordial magnetic field, even if the fermionic modes bound on the wall had ferromagnetic properties. In a particular model with massive (2+1) dimensional fermions bound to a domain wall, previously claimed to exhibit a ferromagnetic behavior, it is explicitly shown that the fermionic system in fact has properties of a normal diamagnetic with the susceptibility vanishing at high temperature.Comment: 8 pages. Modified discussion of the baryon density on an axion domain wal

Indications on the Higgs boson mass from lattice simulations

The `triviality' of $\Phi^4_4$ has been traditionally interpreted within perturbation theory where the prediction for the Higgs boson mass depends on the magnitude of the ultraviolet cutoff $\Lambda$. This approach crucially assumes that the vacuum field and its quantum fluctuations rescale in the same way. The results of the present lattice simulation, confirming previous numerical indications, show that this assumption is not true. As a consequence, large values of the Higgs mass $m_H$ can coexist with the limit $\Lambda\to \infty$. As an example, by extrapolating to the Standard Model our results obtained in the Ising limit of the one-component theory, one can obtain a value as large as $m_H=760 \pm 21$ GeV, independently of $\Lambda$.Comment: 3 pages, 2 figures, Lattice2003(higgs

Identification of a Carcinoembryonic Antigen Gene Family in the Rat

The existence of a carcinoembryonic antigen (CEA)-like gene family in rat has been demonstrated through isolation and sequencing of the N- terminal domain exons of presumably five discrete genes (rnCGM1-5). This finding will allow for the first time the study of functional and clinical aspects of the tumor marker CEA and related antigens in an animal model. Sequence comparison with the corresponding regions of members of the human CEA gene family revealed a relatively low similarity at the amino acid level, which indicates rapid divergence of the CEA gene family during evolution and explains the lack of cross- reactivity of rat CEA-like antigens with antibodies directed against human CEA. The N-terminal domains of the rat CEA-like proteins show structural similarity to immunoglobulin variable domains, including the presence of hypervariable regions, which points to a possible receptor function of the CEA family members. Although so far only one of the five rat CEA-like genes could be shown to be transcriptionally active, multiple mRNA species derived from other members of the rat CEA-like gene family have been found to be differentially expressed in rat placenta and liver

Long-wavelength excitations of Higgs condensates

Quite independently of the Goldstone phenomenon, recent lattice data suggest the existence of gap-less modes in the spontaneously broken phase of a $\lambda \Phi^4$ theory. This result is a direct consequence of the quantum nature of the `Higgs condensate' that cannot be treated as a purely classical c-number field.Comment: 6 page

Dynamical Generation of the Primordial Magnetic Field by Ferromagnetic Domain Walls

The spontaneous generation of uniform magnetic condensate in $QED_3$ gives rise to ferromagnetic domain walls at the electroweak phase transition. These ferromagnetic domain walls are caracterized by vanishing effective surface energy density avoiding, thus, the domain wall problem. Moreover we find that the domain walls generate a magnetic field $B \simeq 10^{24} Gauss$ at the electroweak scale which account for the seed field in the so called dynamo mechanism for the cosmological primordial magnetic field. We find that the annihilation processes of walls with size $R \simeq 10^5 Km$ could release an energy of order $10^{52} erg$ indicating the invisible ferromagnetic walls as possible compact sources of Gamma Ray Bursts.Comment: LaTeX, 8 pages, 1 figur

Analysis of the Size of the Carcinoembryonic Antigen (CEA) Gene Family

Five members of the human CEA gene family [human pregnancy-specific β1-glycoprotein (PSβG), hsCGM1, 2, 3 and 4] have been isolated and identified through sequencing the exons containing their N-terminal domains. Sequence comparisons with published data for CEA and related molecules reveal the existence of highly-conserved gene subgroups within the CEA family. Together with published data eleven CEA family members have so far been determined. Apart from the highly conserved coding sequences, these genes also show strong sequence conservation in their introns, indicating a duplication of whole gene units during the evolution of the CEA gene family