X-ray Fluctuations from the Slim Disk

The responses of perturbations added into the optically thick, advection-dominated accretion disk (ADAD), what we call the slim disk (SD), are investigated through numerical simulations. Although it is proposed that the SD is thermally stable, I find that a perturbation added into the disk is not rapidly damped and moves through the disk in its free-fall time. After the perturbation moves, the global structure of the disk does not vary very much. These facts may account for the substantial variability of the X-ray luminosities of stellar super-luminal jet sources (SLJSs) and Narrow-Line Seyfert 1s (NLS1s).Comment: Poster contribution presented at the Joint MPE,AIP,ESO workshop on NLS1s, Bad Honnef, Dec. 1999, to appear in New Astronomy Reviews; also available at http://wave.xray.mpe.mpg.de/conferences/nls1-worksho

Symmetric and Antisymmetric Spin-Orbit Forces in YN Interaction by a Quark Model

The symmetric and antisymmetric spin-orbit forces (SLS and ALS) in the YN interaction are investigated for relative P-wave systems by a valence quark model with the instanton-induced interaction (III). The size of the adiabatic potential at the zero range is shown for each of the YN channels. The nonlocal RGM potential of the LS and ALS forces are also shown for typical YN channels. The size of ALS is comparable to SLS. The channel dependence of ALS, which is determined by the flavor SU(3) symmetry when the one-gluon exchange (OGE) and/or the meson exchange interaction are used, deviates after introducing III. In most of the two-baryon channels, including the two-nucleon channel, the spin-orbit force of the YN interaction is strong. A few exceptional channels, however, are found where III and OGE are canceled to each other, and the spin-orbit force becomes small.Comment: 5 pages (LaTeX), 2 figures (eps); Talk at the 1st SUT-KEK seminar on 6 Apr 1998 at Science Univ of Tokyo, Noda campu

Hawking fluxes and Anomalies in Rotating Regular Black Holes with a Time-Delay

Based on the anomaly cancellation method we are going to compute the Hawking fluxes (the Hawking thermal flux and the total flux of energy-momentum tensor) from a four-dimensional rotating regular black hole with a time-delay. To this purpose, in the three metrics proposed in arXiv:1510.08828, we try to perform the dimensional reduction in which the anomaly cancellation method is feasible at the near-horizon region in a general scalar field theory. As a result we can demonstrate that the dimensional reduction is possible in two of those metrics. Hence we perform the anomaly cancellation method and compute the Hawking fluxes in those two metrics. Our Hawking fluxes involve the three effects: 1) the quantum gravity effect regularizing the core of the black holes, 2) rotation of the black hole, 3) the time-delay. Further in this paper toward the metric in which the dimensional could not be performed, we argue that it would be some problematic metric, and mention its cause. The Hawking fluxes we compute in this study could be considered to correspond to more realistic Hawking fluxes. Further what Hawking fluxes can be obtained from the anomaly cancellation method would be interesting in terms of the relation between a consistency of quantum field theories and black hole thermodynamics.Comment: 26 pages, 2 figures, accepted version in CQ

Pauli-blocking Effect in a Quark Model

Pauli-Blocking effect on the kinetic term is investigated by employing the quark cluster model. The effect can be understood by the change of the degrees of the mixing between the incoming wave and the 0$\ell$ state of the inter-cluster wave function, which can be expressed by a potential which is highly nonlocal. We look into the properties of this effect by comparing equivalent local potentials. In the channel where the Pauli-blocking effect is small, the on-shell equivalent local potential simulates the nonlocal potential well even for the off-shell behavior. On the other hand, the off-shell behavior is very different from the original one where the effect is large. This off-shell behavior, however, can well be simulated by considering the nonlocal matrix elements only between the $0s$ state and the other states. The energy dependent potentials are also constructed and found to be helpful to understand the energy dependence of the effect.Comment: 14 pages, 12 figure

Accelerating Iterative Detection for Spatially Coupled Systems by Collaborative Training

This letter proposes a novel method for accelerating iterative detection for spatially coupled (SC) systems. An SC system is constructed by one-dimensional coupling of many subsystems, which are classified into training and propagation parts. An irregular structure is introduced into the subsystems in the training part so that information in that part can be detected successfully. The obtained reliable information may spread over the whole system via the subsystems in the propagation part. In order to allow the subsystems in the training part to collaborate, shortcuts between them are created to accelerate iterative detection for that part. As an example of SC systems, SC code-division multiple-access (CDMA) systems are considered. Density Evolution for the SC CDMA systems shows that the proposed method can provide a significant reduction in the number of iterations for highly loaded systems.Comment: accepted for publication on IEEE Commun. Let

Asymptotic Optimality of Massive MIMO Systems Using Densely Spaced Transmit Antennas

This paper considers a deterministic physical model of massive multiple-input multiple-output (MIMO) systems with uniform linear antenna arrays. It is known that the maximum spatial degrees of freedom is achieved by spacing antenna elements at half the carrier wavelength. The purpose of this paper is to investigate the impacts of spacing antennas more densely than the critical separation. The achievable rates of MIMO systems are evaluated in the large-system limit, where the lengths of transmit and receive antenna arrays tend to infinity with the antenna separations kept constant. The main results are twofold: One is that, under a mild assumption of channel instances, spacing antennas densely cannot improve the capacity of MIMO systems normalized by the spatial degrees of freedom. The other is that the normalized achievable rate of quadrature phase-shift keying converges to the normalized capacity achieved by optimal Gaussian signaling, as the transmit antenna separation tends to zero after taking the large-system limit. The latter result is based on mathematical similarity between MIMO transmission and faster-than-Nyquist signaling in signal space representations.Comment: submitted to IEEE Trans. Inf. Theor

QQ-prime curvature and scattering theory on strictly pseudoconvex domains

The $Q$-prime curvature is a local invariant of pseudo-Einstein contact forms on integrable strictly pseudoconvex CR manifolds. The transformation law of the $Q$-prime curvature under scaling is given in terms of a differential operator, called the $P$-prime operator, acting on the space of CR pluriharmonic functions. In this paper, we generalize these objects to the boundaries of asymptotically complex hyperbolic Einstein (ACHE) manifolds, which are partially integrable, strictly pseudoconvex CR manifolds, by using the scattering matrix for ACHE manifolds. In this setting, the $P$-prime operator is a self-adjoint pseudodifferential operator acting on smooth functions and the $Q$-prime curvature is globally determined by the ACHE manifold and the choice of a contact form on the boundary. We prove that the integral of the $Q$-prime curvature is a conformal primitive of the $Q$-curvature; in particular, it defines an invariant of ACHE manifolds whose boundaries admit a contact form with zero $Q$-curvature. We also apply the generalized $Q$-prime curvature to compute the renormalized volume of strictly pseudoconvex domains whose boundaries may not admit pseudo-Einstein structure.Comment: 20 pages, corrected typos and updated reference

Weak Fano threefolds with del Pezzo fibration

This article treats smooth weak Fano 3-folds having an extremal ray of type D. Smooth weak Fano 3-folds with an extremal ray of type D except of degree 6 are classified into 47 deformation types.Comment: 67 page

D-dependence of gap between critical temperatures in one-dimensional gauge theories

We investigate the dimensional dependence (D-dependence) of the difference (gap) between the critical temperatures associated with the uniform/non-uniform and non-uniform/gapped transitions in the large-N bosonic gauge theories with D matrix scalar fields on a circled space. We use the equations describing these critical temperatures given in the 1/D expansion arXiv:0910.4526. These transitions are related with Gregory-Laflamme instabilities in the gravities and Rayleigh-Plateau instabilities in the fluid dynamics, and qualitative similarities between these are expected. We find that the tendency in the D-dependence of the gap is opposite from those in the gravity and fluid side. This is interesting as a counterexample to the gauge/gravity and gauge/fluid correspondences.Comment: 30 pages, published versio

Domain-area distribution anomaly in segregating multicomponent superfluids

The domain-area distribution in the phase transition dynamics of ${\rm Z}_2$ symmetry breaking is studied theoretically and numerically for segregating binary Bose--Einstein condensates in quasi-two-dimensional systems. Due to the dynamic scaling law of the phase ordering kinetics, the domain-area distribution is described by a universal function of the domain area, rescaled by the mean distance between domain walls. The scaling theory for general coarsening dynamics in two dimensions hypothesizes that the distribution during the coarsening dynamics has a hierarchy with the two scaling regimes, the microscopic and macroscopic regimes with distinct power-law exponents. The power law in the macroscopic regime, where the domain size is larger than the mean distance, is universally represented with the Fisher's exponent of the percolation theory in two dimensions. On the other hand, the power-law exponent in the microscopic regime is sensitive to the microscopic dynamics of the system. This conjecture is confirmed by large-scale numerical simulations of the coupled Gross--Pitaevskii equation for binary condensates. In the numerical experiments of the superfluid system, the exponent in the microscopic regime anomalously reaches to its theoretical upper limit of the general scaling theory. The anomaly comes from the quantum-fluid effect in the presence of circular vortex sheets, described by the hydrodynamic approximation neglecting the fluid compressibility. It is also found that the distribution of superfluid circulation along vortex sheets obeys a dynamic scaling law with different power-law exponents in the two regimes. An analogy to quantum turbulence on the hierarchy of vorticity distribution and the applicability to chiral superfluid $^3$He in a slab are also discussed.Comment: 9 pages, 5 figure