Deconfinement transition for nonzero baryon density in the Field Correlator Method

Deconfinement phase transition due to disappearance of confining colorelectric field correlators is described using nonperturbative equation of state. The resulting transition temperature $T_c(\mu)$ at any chemical potential $\mu$ is expressed in terms of the change of gluonic condensate $\Delta G_2$ and absolute value of Polyakov loop $L_{fund} (T_c)$, known from lattice and analytic data, and is in good agreement with lattice data for $\Delta G_2 \approx 0.0035$ GeV$^4$. E.g. $T_c(0) =0.27; 0.19; 0.17$ GeV for $n_f=0,2,3$ respectively.Comment: 8 pages, 1 figure, LaTeX2e; some typos correcte

Neutrino Velocity and Neutrino Oscillations

We study distances of propagation and the group velocities of the muon neutrinos in the presence of mixing and oscillations assuming that Lorentz invariance holds. Oscillations lead to distortion of the $\nu_\mu$ wave packet which, in turn, changes the group velocity and the distance $\nu_\mu$ travels. We find that the change of the distance, $d_{osc}$, is proportional to the length of the wave packet, $\sigma_x$, and the oscillation phase, $\phi_p$, acquired by neutrinos in the $\pi-$ and $K-$ meson decay tunnel where neutrino wave packet is formed: $d_{osc} \propto \sigma \phi_p$. Although the distance $d_{osc}$ may effectively correspond to the superluminal motion, the effect is too tiny ($\sim 10^{- 5}$ cm) to be reconciled with the OPERA result. We analyze various possibilities to increase $d_{osc}$ and discuss experimental setups in which $d_{osc}$ (corresponding to the superluminal motion) can reach an observable value $\sim 1$ m.Comment: LaTeX, 24 pages, 1 eps figure, matches to the published versio

Dynamics of confined gluons

Propagation of gluons in the confining vacuum is studied in the framework of the background perturbation theory, where nonperturbative background contains confining correlators. Two settings of the problem are considered. In the first the confined gluon is evolving in time together with static quark and antiquark forming the one-gluon static hybrid. The hybrid spectrum is calculated in terms of string tension and is in agreement with earlier analytic and lattice calculations. In the second setting the confined gluon is exchanged between quarks and the gluon Green's function is calculated, giving rise to the Coulomb potential modified at large distances. The resulting screening radius of 0.5 fm presents a serious problem when confronting with lattice and experimental data. A possible solution of this discrepancy is discussed.Comment: 17 pages, no figures; v2: minor numerical changes in the tabl

Conductivity and Atomic Structure of Isolated Multiwalled Carbon Nanotubes

We report associated high resolution transmission electron microscopy (HRTEM) and transport measurements on a series of isolated multiwalled carbon nanotubes. HRTEM observations, by revealing relevant structural features of the tubes, shed some light on the variety of observed transport behaviors, from semiconducting to quasi-metallic type. Non Ohmic behavior is observed for certain samples which exhibit "bamboo like" structural defects. The resistance of the most conducting sample, measured down to 20 mK, exhibits a pronounced maximum at 0.6 K and strong positive magnetoresistance.Comment: 4 pages, 4 eps figure

Nonperturbative mechanisms of strong decays in QCD

Three decay mechanisms are derived systematically from the QCD Lagrangian using the field correlator method. Resulting operators contain no arbitrary parameters and depend only on characteristics of field correlators known from lattice and analytic calculations. When compared to existing phenomenological models, parameters are in good agreement with the corresponding fitted values.Comment: 12 pages, latex2

QCD string and the Lorentz nature of confinement

We address the question of the Lorentz nature of the effective long-range interquark interaction generated by the QCD string with quarks at the ends. Studying the Dyson-Schwinger equation for a heavy-light quark-antiquark system, we demonstrate explicitly how a Lorentz-scalar interaction appears in the Diraclike equation for the light quark, as a consequence of chiral symmetry breaking. We argue that the effective interquark interaction in the Hamiltonian of the QCD string with quarks at the ends stems from this effective scalar interaction.Comment: LaTeX2e, 5 pages, uses jetpl.cls (included), to appear in JETP Let