Effect of Thermal Fluctuation on Spectral Function for the Tomonaga-Luttinger Model

We examine the spectral function of the single electron Green function at finite temperatures for the Tomonaga-Luttinger model which consists of the mutual interaction with only the forward scattering. The spectral weight, which is calculated as a function of the frequency with the fixed wave number, shows that several peaks originating in the excitation spectra of charge and spin fluctuations vary into a single peak by the increase of temperature.Comment: 10 pages, 6 eps figure

Accretion Phase of Star Formation in Clouds with Different Metallicities

The main accretion phase of star formation is investigated in clouds with different metallicities in the range of 0 \le Z \le Z_\odot, resolving the protostellar radius. Starting from a near-equilibrium prestellar cloud, we calculate the cloud evolution up to \sim100 yr after the first protostar formation. The star formation process considerably differs between clouds with lower (Z \le 10^-4 Z_\odot) and higher (Z > 10^-4 Z_\odot) metallicities. Fragmentation frequently occurs and many protostars appear without forming a stable circumstellar disc in lower-metallicity clouds. In these clouds, although protostars mutually interact and some are ejected from the cloud centre, many remain as a small stellar cluster. In contrast, higher-metallicity clouds produce a single protostar surrounded by a nearly stable rotation-supported disc. In these clouds, although fragmentation occasionally occurs in the disc, the fragments migrate inwards and finally fall onto the central protostar. The difference in cloud evolution is due to different thermal evolutions and mass accretion rates. The thermal evolution of the cloud determines the emergence and lifetime of the first core. The first core develops prior to the protostar formation in higher-metallicity clouds, whereas no (obvious) first core appears in lower-metallicity clouds. The first core evolves into a circumstellar disc with a spiral pattern, which effectively transfers the angular momentum outwards and suppresses frequent fragmentation. In lower-metallicity clouds, the higher mass accretion rate increases the disc surface density within a very short time, rendering the disc unstable to self-gravity and inducing vigorous fragmentation.Comment: Accepted for publication in MNRA

Universal low-temperature properties of quantum and classical ferromagnetic chains

We identify the critical theory controlling the universal, low temperature, macroscopic properties of both quantum and classical ferromagnetic chains. The theory is the quantum mechanics of a single rotor. The mapping leads to an efficient method for computing scaling functions to high accuracy.Comment: 4 pages, 2 tables and 3 Postscript figure

Abelian monopoles and center vortices in Yang-Mills plasma

Condensation of the Abelian monopoles and the center vortices leads to confinement of color in low temperature phase of Yang-Mills theory. We stress that these topological magnetic degrees of freedom are also very important in the deconfinement regime: at the point of the deconfinement phase transition both the monopoles and the vortices are released into the thermal vacuum contributing, in particular, to the equation of state and, definitely, to transport properties of the hot gluonic medium. Thus, we argue that a novel, magnetic component plays a crucial role. On the other hand, it was demonstrated that an effective three-dimensional description can be brought, beginning with high temperatures, down to the critical temperature by postulating existence of a system of 3d Higgs fields. We propose to identify the 3d color-singlet Higgs field with the 3d projection of the 4d magnetic vortices. Such identification fits well the 3d properties of the theory and contributes to interpretation of the magnetic component of the Yang-Mills plasma.Comment: 5 pages, 3 figures; talk at Quark Confinement and the Hadron Spectrum, September 1-6 2008, Mainz, German

First-order quantum correction to the Larmor radiation from a moving charge in a spatially homogeneous time-dependent electric field

First-order quantum correction to the Larmor radiation is investigated on the basis of the scalar QED on a homogeneous background of time-dependent electric field, which is a generalization of a recent work by Higuchi and Walker so as to be extended for an accelerated charged particle in a relativistic motion. We obtain a simple approximate formula for the quantum correction in the limit of the relativistic motion when the direction of the particle motion is parallel to that of the electric field.Comment: 12 pages, 2 figures, accepted for publication in Physical Review

Gluon propagators and center vortices at finite temperature

We study influence of center vortices on infrared properties of gluons in the deconfinement phase of quenched QCD. We observe a significant suppression of the magnetic component of the gluon propagator in the low-momentum region after the vortices are removed from the gluon configurations. The propagator of the electric gluon stays almost unaffected by the vortex removal. Our results demonstrate that the center vortices are responsible for important nonperturbative properties of the magnetic component of the quark-gluon plasma.Comment: 7 pages, 8 figures, talk presented at 27th International Symposium on Lattice Field Theory (Lattice 2009), Beijing, 26-31 Jul 200

Singularity-matching peaks in superconducting single-electron transistor

We report the experimental observation of the recently predicted peaks on the I-V curve of the superconducting single-electron transistor at relatively high temperatures. The peaks are due to the matching of singularities in the quasiparticle density of states in two electrodes of a tunnel junction. The energy shift due to Coulomb blockade provides the matching at finite voltage.Comment: 11 pages (RevTeX), 3 figure