A Strategy to Study Confinement in QCD

The order and the universality class of the deconfining phase transition can provide insight into the mechanism of color confinement, in particular for N_f=2. The mechanism of confinement by monopole condensation is reviewed.Comment: Presented at IRQCD '06 UERJ Rio de Janeiro (Brasil) 5-9 June 2006. 6 pages, 3 figure

Confinement of Color: Recent Progress

Recent progress done in Pisa on the subject is presented. It is shown that dual superconductivity of the vacuum or absence of it is an intrinsic property of QCD vacuum, independent of the choice of the abelian projection. The order of the deconfining phase transition in $N_f=2$ QCD is studied as a key to understand the mechanism of confinement.Comment: Talk at Confinement 2003, Tokyo, july 2003, to appear in the proceedings. 10 pages, 2 figure

Ultrarelativistic electron states in a general background electromagnetic field

The feasibility of obtaining exact analytical results in the realm of QED in the presence of a background electromagnetic field is almost exclusively limited to a few tractable cases, where the Dirac equation in the corresponding background field can be solved analytically. This circumstance has restricted, in particular, the theoretical analysis of QED processes in intense laser fields to within the plane-wave approximation even at those high intensities, achievable experimentally only by tightly focusing the laser energy in space. Here, within the Wentzel-Kramers-Brillouin (WKB) or eikonal approximation, we construct analytically single-particle electron states in the presence of a background electromagnetic field of general space-time structure in the realistic assumption that the initial energy of the electron is the largest dynamical energy scale in the problem. The relatively compact expression of these states opens, in particular, the possibility of investigating analytically strong-field QED processes in the presence of spatially focused laser beams, which is of particular relevance in view of the upcoming experimental campaigns in this field.Comment: 7 pages, 1 figur