External Field Dependence of Deconfinement Temperature in SU(3)

We study vacuum dynamics of SU(3) lattice gauge theory at finite temperature. Using the lattice Schr\"odinger functional, SU(3) vacuum is probed by means of an external constant Abelian chromomagnetic field. Our preliminary numerical data suggest that, by increasing the strength of the applied external field, deconfinement temperature decreases towards zero. This means that strong enough Abelian chromomagnetic fields destroy confinement of color.Comment: Lattice2001(confinement); 3 pages, 4 figure

Nf_f = 1 QCD in External Magnetic Fields: Staggered Fermions

We investigate N$_f$ = 1 QCD in external magnetic fields on the lattice. The background field is introduced by means of the so-called Schrodinger functional. We adopt standard staggered fermions with constant bare mass $am = 0.025$ and magnetic fields with constant magnetic flux up to $a^2 e H \simeq 2.3562$. We find that the the deconfinement and chiral symmetry restoration temperatures do not depend on the strength of the applied magnetic field. Our method allow us to easily study the effects of the external magnetic fields on the QCD thermodynamics. We determine the influences of applied magnetic fields to the free energy, pressure, and equation of state of strongly interacting matter.Comment: 21 pages, 11 figures; revised version accepted for publication in JHE

Study of Confinement Using the Schroedinger Functional

We use a gauge-invariant effective action defined in terms of the lattice Schroedinger functional to investigate vacuum dynamics and confinement in pure lattice gauge theories. After a brief introduction to the method, we report some numerical results.Comment: Contributed to workshop GISELDA, Frascati, Italy, 14-18 Jan 200

The Higgs boson: from the lattice to LHC

We discuss the triviality and spontaneous symmetry breaking scenario where the Higgs boson without self-interaction coexists with spontaneous symmetry breaking. We argue that non perturbative lattice investigations support this scenario. Moreover, from lattice simulations we predict that the Higgs boson is rather heavy. We estimate the Higgs boson mass $m_H = 754 \pm 20 {\text{(stat)}} \pm 20 {\text{(syst)}} {\text{GeV}}$ and the Higgs total width $\Gamma(H) \simeq 340 {\text{GeV}}$.Comment: 15 pages, 3 figures, revised version accepted for publication on ISRN High Energy Physic

SU(2) vacuum dynamics in applied external magnetic field

The vacuum dynamics of SU(2) lattice gauge theory is studied by means of a gauge-invariant effective action, both at zero and finite temperature. Working with lattices up to 32^4 we check the scaling of the energy density with the magnetic length. We find that the screening at zero temperature of the applied external magnetic field weakens by increasing the temperature.Comment: LATTICE98(confine

Deconfinement phase transitions in external fields

We compare vacuum dynamics of abelian versus non abelian lattice gauge theories in presence of external fields. We find that the deconfinement temperature of non abelian theories depends on the strength of a constant abelian chromomagnetic field end eventually goes to zero. On the contrary such an effect is not shared by abelian theories. We argue on the relevance of this result to understand the QCD vacuum.Comment: Poster presented at Lattice2005 (Topology and Confinement), Dublin, July 25-30, 2005; 6 pages, 3 figures, uses PoS.cls; to appear in Proceedings of Scienc

Full QCD in external chromomagnetic field

We investigate the deconfining phase transition in full QCD with two flavors of staggered fermions in presence of a constant abelian chromomagnetic field. We find that the deconfinement temperature decreases and eventually goes to zero by increasing the strength of the chromomagnetic field. Moreover our results suggest that the chiral transition coincides with the deconfinement transition and therefore even the chiral critical temperature depends on the applied chromomagnetic field. We also find that the chiral condensate increases with the strength of the chromomagnetic field.Comment: 7 pages, 5 figures, Lattice 2006 (Topology and Confinement

Perturbing QCD with external fields

We present some up-to-date results on QCD phase transition in a chromomagnetic constant background field and in an abelian monopole background field. Our results indicate that the QCD critical temperature is not modified by a monopole background field, whilst it is modified by a constant chromomagnetic field. We improve our earlier estimate of the QCD critical parameters in a chromomagnetic background field by performing lattice simulations with weaker fields.Comment: contribution to the XXV International Symposium on Lattice Field Theory, July 30 - August 4 2007, Regensburg, Germany, 7 page

Critical line of 2+1 flavor QCD: Toward the continuum limit

We determine the continuum limit of the curvature of the pseudocritical line of QCD with $n_f$=2+1 staggered fermions at nonzero temperature and quark density. We perform Monte Carlo simulations at imaginary baryon chemical potentials, adopting the HISQ/tree action discretization, as implemented in the code by the MILC collaboration. Couplings are adjusted so as to move on a line of constant physics, as determined in Ref.~\cite{Bazavov:2011nk}, with the strange quark mass $m_s$ fixed at its physical value and a light-to-strange mass ratio $m_l/m_s=1/20$. The chemical potential is set at the same value for the three quark species, $\mu_l=\mu_s\equiv \mu$. We attempt an extrapolation to the continuum using the results on lattices with temporal size up to $L_t=12$. Our estimate for the continuum value of the curvature $\kappa$ at zero baryon density, $\kappa=0.020(4)$, is compared with recent lattice results and with experimental determinations of the freeze-out curve.Comment: 10 pages, 4 figures, 16 tables; modified title and abstract, added two tables and a few comments in the text, added appendix with 13 tables; version to appear on Phys. Rev.