Immittance Matching for Multi-dimensional Open-system Photonic Crystals

An electromagnetic (EM) Bloch wave propagating in a photonic crystal (PC) is characterized by the immittance (impedance and admittance) of the wave. The immittance is used to investigate transmission and reflection at a surface or an interface of the PC. In particular, the general properties of immittance are useful for clarifying the wave propagation characteristics. We give a general proof that the immittance of EM Bloch waves on a plane in infinite one- and two-dimensional (2D) PCs is real when the plane is a reflection plane of the PC and the Bloch wavevector is perpendicular to the plane. We also show that the pure-real feature of immittance on a reflection plane for an infinite three-dimensional PC is good approximation based on the numerical calculations. The analytical proof indicates that the method used for immittance matching is extremely simplified since only the real part of the immittance function is needed for analysis without numerical verification. As an application of the proof, we describe a method based on immittance matching for qualitatively evaluating the reflection at the surface of a semi-infinite 2D PC, at the interface between a semi-infinite slab waveguide (WG) and a semi-infinite 2D PC line-defect WG, and at the interface between a semi-infinite channel WG and a semi-infinite 2D PC slab line-defect WG.Comment: 8 pages, 6 figure

Magnetized Accretion-Ejection Structures: 2.5D MHD simulations of continuous Ideal Jet launching from resistive accretion disks

We present numerical magnetohydrodynamic (MHD) simulations of a magnetized accretion disk launching trans-Alfvenic jets. These simulations, performed in a 2.5 dimensional time-dependent polytropic resistive MHD framework, model a resistive accretion disk threaded by an initial vertical magnetic field. The resistivity is only important inside the disk, and is prescribed as eta = alpha_m V_AH exp(-2Z^2/H^2), where V_A stands for Alfven speed, H is the disk scale height and the coefficient alpha_m is smaller than unity. By performing the simulations over several tens of dynamical disk timescales, we show that the launching of a collimated outflow occurs self-consistently and the ejection of matter is continuous and quasi-stationary. These are the first ever simulations of resistive accretion disks launching non-transient ideal MHD jets. Roughly 15% of accreted mass is persistently ejected. This outflow is safely characterized as a jet since the flow becomes super-fastmagnetosonic, well-collimated and reaches a quasi-stationary state. We present a complete illustration and explanation of the `accretion-ejection' mechanism that leads to jet formation from a magnetized accretion disk. In particular, the magnetic torque inside the disk brakes the matter azimuthally and allows for accretion, while it is responsible for an effective magneto-centrifugal acceleration in the jet. As such, the magnetic field channels the disk angular momentum and powers the jet acceleration and collimation. The jet originates from the inner disk region where equipartition between thermal and magnetic forces is achieved. A hollow, super-fastmagnetosonic shell of dense material is the natural outcome of the inwards advection of a primordial field.Comment: ApJ (in press), 32 pages, Higher quality version available at http://www-laog.obs.ujf-grenoble.fr/~fcass

Experimental Constraints on the Neutrino Oscillations and a Simple Model of Three Flavour Mixing

A simple model of the neutrino mixing is considered, which contains only one right-handed neutrino field, coupled via the mass term to the three usual left-handed fields. This is a simplest model that allows for three-flavour neutrino oscillations. The existing experimental limits on the neutrino oscillations are used to obtain constraints on the two free mixing parameters of the model. A specific sum rule relating the oscillation probabilities of different flavours is derived.Comment: 10 pages, 3 figures in post script, Latex, IFT 2/9

Is CP Violation Observable in Long Baseline Neutrino Oscillation Experiments ?

We have studied CP violation originated by the phase of the neutrino mixing matrix in the long baseline neutrino oscillation experiments. The direct measurements of CP violation is the difference of the transition probabilities between CP-conjugate channels. In those experiments, the CP violating effect is not suppressed if the highest neutrino mass scale is taken to be 1\sim 5 \eV, which is appropriate for the cosmological hot dark matter. Assuming the hierarchy for the neutrino masses, the upper bounds of CP violation have been caluculated for three cases, in which mixings are constrained by the recent short baseline ones. The calculated upper bounds are larger than $10^{-2}$, which will be observable in the long baseline accelerator experiments. The matter effect, which is not CP invariant, has been also estimated in those experiments.Comment: 28 pages, LaTex file, 6 figures included using epsfig Matter effect is estimated(Figs.3(a) (b)). Physical parameters are change

A New Upper Limit for the Tau-Neutrino Magnetic Moment

Using a prompt neutrino beam in which a nu_tau component was identified for the first time, the nu_tau magnetic moment was measured based on a search for an anomalous increase in the number of neutrino-electron interactions. One such event was observed when 2.3 were expected from background processes, giving an upper 90% confidence limit of 3.9x10^-7 Bohr magnetons.Comment: 9 pages; 1 figur

Accelerator and Reactor Neutrino Oscillation Experiments in a Simple Three-Generation Framework

We present a new approach to the analysis of neutrino oscillation experiments, in the one mass-scale limit of the three-generation scheme. In this framework we reanalyze and recombine the most constraining accelerator and reactor data, in order to draw precise bounds in the new parameter space. We consider our graphical representations as particularly suited to show the interplay among the different oscillation channels. Within the same framework, the discovery potential of future short and long baseline experiments is also investigated, in the light of both the recent signal from the LSND experiment and the atmospheric neutrino anomaly.Comment: uuencoded compressed tar file. Figures (13) available by ftp to ftp://eku.sns.ias.edu/pub/lisi/ (192.16.204.30). Submitted to Physical Review

A first measurement of the interaction cross section of the tau neutrino

The DONuT experiment collected data in 1997 and published first results in 2000 based on four observed $\nu_\tau$ charged-current (CC) interactions. The final analysis of the data collected in the experiment is presented in this paper, based on $3.6 \times 10^{17}$ protons on target using the 800 GeV Tevatron beam at Fermilab. The number of observed $\nu_\tau$ CC interactions is 9, from a total of 578 observed neutrino interactions. We calculated the energy-independent part of the tau-neutrino CC cross section ($\nu + \bar \nu$), relative to the well-known $\nu_e$ and $\nu_\mu$ cross sections. The ratio $\sigma(\nu_\tau)$/$\sigma(\nu_{e,\mu})$ was found to be $1.37\pm0.35\pm0.77$. The $\nu_\tau$ CC cross section was found to be $0.72 \pm 0.24\pm0.36 \times 10^{-38}$ cm$^{2}\rm{GeV}^{-1}$. Both results are in agreement the Standard Model.Comment: 37 pages, 15 figure

In vitro recellularization of aorta scaffolds prepared by sonication treatment

Sonication treatment is used in the preparation of bioscaffolds that was able to support repopulation of vascular smooth muscle cells (VSMCs) upon cell-seeding. The aim of this study is to investigate the ability of sonicatedly decellularized tissue to repopulate VSMCs after 6 days of cell-seeding. In this study, sample of aorta tissues are decellularized by sonication treatment in 0.1% and 2% sodium dodecyl sulfate (SDS) detergent for 10 hours. It was followed by washing process with PBS solution for 5 days. Decellularized aorta tissues are then cell seeded with VSMCs by static seeding in 96-well plate containing Dulbecco's Modified Eagle Medium (DMEM) at 37°C. The infiltrations of VSMCs onto decellularized tissues are evaluated by comparison of Hematoxylin-Eosin (H-E) staining at 0 and 6 days of cell-seeding. The histological results of cell-seeding showed that VSMCs are able to infiltrate onto the decellularized tissues. From the results, sonicatedly decellularized tissue treated in 0.1% and 2% SDS, seeded with VSMCs showed infiltration depth of 0.43 mm and 0.35 mm, respectively. Hence, a sonicated decellularized tissue treated with 0.1% and 2% SDS was shown to support the repopulation of VSMCs

Heat-capacity anomalies at TscT_{sc} and T∗T^{*} in the ferromagnetic superconductor UGe2_2

The heat-capacity and magnetization measurements under high pressure have been carried out in a ferromagnetic superconductor UGe$_2$. Both measurements were done using a same pressure cell in order to obtain both data for one pressure. Contrary to the heat capacity at ambient pressure, an anomaly is found in the heat capacity at the characteristic temperature $T^{*}$ where the magnetization shows an anomalous enhancement under high pressure where the superconductivity appears. This suggests that a thermodynamic phase transition takes place at $T^{*}$ at least under high pressure slightly below $P_{c}^{*}$ where $T^{*}$ becomes zero. The heat-capacity anomaly associated with the superconducting transition is also investigated, where a clear peak of $C/T$ is observed in a narrow pressure region ($\Delta P \sim 0.1$ GPa) around $P_{c}^{*}$ contrary to the previous results of the resistivity measurement. Present results suggest the importance of the thermodynamic critical point $P_{c}^{*}$ for the appearance of the superconductivity.Comment: 4 pages, 4 figures, to appear in Phys. Rev. B, Rapid Communication

Neutrino Masses and Mixing: Evidence and Implications

Measurements of various features of the fluxes of atmospheric and solar neutrinos have provided evidence for neutrino oscillations and therefore for neutrino masses and mixing. We review the phenomenology of neutrino oscillations in vacuum and in matter. We present the existing evidence from solar and atmospheric neutrinos as well as the results from laboratory searches, including the final status of the LSND experiment. We describe the theoretical inputs that are used to interpret the experimental results in terms of neutrino oscillations. We derive the allowed ranges for the mass and mixing parameters in three frameworks: First, each set of observations is analyzed separately in a two-neutrino framework; Second, the data from solar and atmospheric neutrinos are analyzed in a three active neutrino framework; Third, the LSND results are added, and the status of accommodating all three signals in the framework of three active and one sterile light neutrinos is presented. We review the theoretical implications of these results: the existence of new physics, the estimate of the scale of this new physics and the lessons for grand unified theories, for supersymmetric models with R-parity violation, for models of extra dimensions and singlet fermions in the bulk, and for flavor models.Comment: Added note on the effects of KamLAND results. Two new figure