We have introduced defects in ZnO epitaxial thin films by swift heavy Ag ion irradiation and investigated systematically their magnetic, electrical and optical properties. Oxygen annealed ZnO films are epitaxial single crystals that exhibit no long-range magnetic order. However, in this paper it is shown that room-temperature ferromagnetism (RTFM) can be introduced in a controlled manner in the...

We investigate angular and energy distributions of medium-induced gluon emission off a quark-antiquark antenna in the framework of perturbative QCD as an attempt toward understanding, from first principles, jet evolution inside the quark-gluon plasma. In-medium color coherence between emitters, neglected in all previous calculations, leads to a novel mechanism of soft-gluon radiation. The struc...

Ultra high energy collisions between heavy nuclei can be employed to experimentally probe the QCD properties of dense quark-gluon systems [1, 2, 3, 4, 5]. The properties of the high density quark gluon system have also been compared to a color glass[6, 7, 8, 9, 10, 11, 12, 13]. High energy proton-proton scattering also probes the QCD vacuum. The QCD vacuum differs from the QED vacuum via proper...

We find the exact solution of a recently proposed model of the lattice gauge theory induced by heavy scalar field in adjoint representation at N = ∞ for arbitrary dimension D. The nonlinear integral equation for the gauge invariant density of eigenvalues of the vacuum average of the scalar field is derived. In the continuum limit, the density grows as φ α where α = 1 +

In ultrarelativistic heavy ion collisions a finite size QCD medium is created. In this paper we compute radiative energy loss to zeroth order in opacity by taking into account finite size effects. Transition radiation occurs on the boundary between the finite size medium and the vacuum, and we show that it lowers the difference between medium and vacuum zeroth order radiative energy loss relati...

The three-loop vacuum polarization function Π(q 2) induced by a massive quark is calculated. A comprehensive description of the method is presented. From the imaginary part the O(α 2 s) result for the production of heavy quarks R(s) = σ(e + e − → hadrons)/σ(e + e − → µ + µ −) can be extracted. Explicit formulae separated into the different colour factors are given.

The leading nonperturbative QCD corrections to the one gluon exchange quark-quark, quark-antiquark and q ¯ q pair-excitation potentials are derived by using a covariant form of nonlocal two-quark and two-gluon vacuum expectation values. Our numerical calculation indicates that the correction of quark and gluon condensates to the quark-antiquark potential improves the heavy quarkonium spectra to...

Nonperturbative nolocal structure of QCD vacuum is well described by instanton model. Specific helicity and flavor structure of zero modes of quarks in instanton field allows simultaneously to explain some important features of lowand highenergy hadron phenomemology. The basic characteristics of hadron spectrum, partonic sum rules, heavy-quark potential are briefly discussed within the instanto...

We investigate the production of gluon pairs from a space-time dependent classical chromofield via vacuum polarization within the framework of the background field method of QCD. The investigation of the production of gluon pairs is important in the study of the evolution of the quark-gluon plasma in ultra-relativistic heavy-ion collisions at RHIC and LHC.

The vacuum wave functional of Coulomb gauge Yang-Mills theory is determined within the vari-ational principle and used to calculate various Green functions and observables. The results show that heavy quarks are confined by a linearly rising potential and gluons cannot propagate over large distances. The 't Hooft loop shows a perimeter law and thus also indicates confinement.