Nonequilibrium Perturbative Formalism and Spectral Function for the Anderson Model

The present work is based on the nonequilibrium perturbative formalism. There the self-energies are derived up to the forth-order. In consequence, it proves that the nonequilibrium (real-time) perturbative expansion can be connected with the Matsubara imaginary-time perturbative expansion for equilibrium. As the numerical results, the Kondo resonance still disappears for bias voltage exceeding the Kondo temperatures, as observed in experiments of two terminal systems.Comment: Some conclusions and typos are corrected;the derived expressions and numerical results are unchange

Excitation of Low-Frequency QPOs in Black Hole Accretion Flows

We present the results of global three dimensional magneto-hydrodynamic simulations of black hole accretion flows. We focus on the dependence of numerical results on the gas temperature Tout supplied from the outer region. General relativistic effects are taken into account using the pseudo-Newtonian potential. We ignore the radiative cooling of the accreting gas. The initial state is a torus whose density maximum is at 35rs or 50rs from the gravitating center, where rs is the Schwarzschild radius. The torus is initially threaded by a weak azimuthal magnetic field. We found that mass accretion rate and the mass outflow rate strongly depend on the temperature of the initial torus. The ratio of the average Maxwell stress generated by the magneto-rotational instability (MRI) to gas pressure is alpha ~0.05 in the hot torus and alpha ~ 0.01 in the cool torus. In the cool model, a constant angular momentum inner torus is formed around 4-8rs. This inner torus deforms itself from a circle to a crescent quasi-periodically. During this deformation, the mass accretion rate, the magnetic energy and the Maxwell stress increase. As the magnetic energy is released, the inner torus returns to a circular shape and starts the next cycle. Power spectral density (PSD) of the time variation of the mass accretion rate in the cool model has a low frequency peak around 10Hz when we assumed a 10 solar mass black hole. The PSD of the hot model is flat in 1-30Hz. The slope of the PSD in the cool model is steeper than that in the hot model in 30-100Hz. The mass outflow rate in the low temperature model also shows quasi-periodic oscillation. Intermittent outflows are created in both models. The outflow speed is $0.01c - 0.05c$.Comment: 22 pages, 17 figures, accepted for publication in PASJ (PASJ,60,pp.613-626). Replaced to high resolution versio

The Primordial Origin Model of Magnetic Fields in Spiral Galaxies

We propose a primordial-origin model for the composite configurations of global magnetic fields in spiral galaxies. We show that uniform tilted magnetic field wound up into a rotating disk galaxy can evolve into composite magnetic configurations comprising bisymmetric spiral (S=BSS), axisymmetric spiral (A=ASS), plane-reversed spiral (PR), and/or ring (R) fields in the disk, and vertical (V) fields in the center. By MHD simulations we show that these composite galactic fields are indeed created from weak primordial uniform field, and that the different configurations can co-exist in the same galaxy. We show that spiral fields trigger the growth of two-armed gaseous arms. The centrally accumulated vertical fields are twisted and produce jet toward the halo. We find that the more vertical was the initial uniform field, the stronger is the formed magnetic field in the galactic disk.Comment: 11 pages, 14 figures, accepted for publication in PAS