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Chemical mechanisms with oscillations or bistability undergo Hopf or saddle-node bifurcations on parameter space hypersurfaces, which intersect in codimension-2 Takens–Bogdanov bifurcation hypersurfaces. This paper develops a general method for deriving equations for these hypersurfaces in terms of rate constants and other experimentally controllable parameters. These equations may be used to obtain better rate constant values and confirm mechanisms from experimental data. The method is an extension of stoichiometric network analysis, which can obtain bifurcation hypersurface equations in special (h,j) parameters for small networks. This paper simplifies the approach using Orlando’s theorem and takes into consideration Wegscheider’s thermodynamic constraints on the rate constants. Large realistic mechanisms can be handled by a systematic method for approximating networks near bifurcation points using essential extreme currents. The algebraic problem of converting the bifurcation equations to rate constants is much more tractable for the simplified networks, and agreement is obtained with numerical calculations. The method is illustrated using a seven-species model of the Belousov–Zhabotinskii system, for which the emergence of Takens–Bogdanov bifurcation points is explained by the presence of certain positive and negative feedback cycles. [ABSTRACT FROM AUTHOR]

This is the second of a series of papers aimed to look for an explanation on the generation of high frequency quasi-periodic oscillations (QPOs) in accretion disks around neutron star, black hole, and white dwarf binaries. The model is inspired by the general idea of a resonance mechanism in the accretion disk oscillations as was already pointed out by Abramowicz and Klu’zniak (2001). In a first paper (P'etri, 2005a, paper I), we showed that a rotating misaligned magnetic field of a neutron star gives rise to some resonances close to the inner edge of the accretion disk. In this second paper, we suggest that this process does also exist for an asymmetry in the gravitational potential of the compact object. We prove that the same physics applies, at least in the linear stage of the response to the disturbance in the system. This kind of asymmetry is well suited for neutron stars or white dwarfs possessing an inhomogeneous interior allowing for a deviation from a perfectly spherically symmetric gravitational field. After a discussion on the magnitude of this deformation applied to neutron stars, we show by a linear analysis that the disk initially in a cylindrically symmetric stationary state is subject to {three kinds of resonances: a corotation resonance, a Lindblad resonance due to a driven force and a parametric resonance}. In a second part, we focus on the linear response of a thin accretion disk in the 2D limit. {Waves are launched at the aforementioned resonance positions and propagate in some permitted regions inside the disk, according to the dispersion relation obtained by a WKB analysis}. In a last part, these results are confirmed and extended via non linear hydrodynamical numerical simulations performed with a pseudo-spectral code solving Euler's equations in a 2D cylindrical coordinate frame. {We found that for a weak potential perturbation, the Lindblad resonance is the only effective mechanism producing a significant density fluctuation}. In a last step, we replaced the Newtonian potential by the so called logarithmically modified pseudo-Newtonian potential in order to take into account some general-relativistic effects like the innermost stable circular orbit (ISCO). The latter potential is better suited to describe the close vicinity of a neutron star or a black hole. However, from a qualitative point of view, the resonance conditions remain the same. The highest kHz QPOs are then interpreted as the orbital frequency of the disk at locations where the response to the resonances are maximal. It is also found that strong gravity is not required to excite the resonances. [ABSTRACT FROM AUTHOR]

The balanced comparator is an essential part of RSFQ-based readout for superconducting qubits. In this paper we report measurements of the sensitivity of the balanced comparator fabricated in a specialized 30 A/cm2 process with 3.6 μA critical currents and measured at 30-500 mK. At sampling frequency of 3.5 GHz the measured gray zone is ΔI = 104 nA. Due to electron overheating in the shunt resistors the effective noise temperature is 140 mK. The gray zone has a strong dependence on sampling frequency above 5 GHz due to over-clocking. Related measurements have been reported where cooling fins and reduced critical current density of 10 A/cm2 were used, and a quantum limited gray zone of 40 nA was achieved. This makes single shot readout possible for the phase, RF-SQUID and persistent current qubits. The readout speed is 30-50 ps, which is quite favorable for error correction schemes. [ABSTRACT FROM AUTHOR]

In this paper we summarize the status of neutrino oscillations and neutrino direct mass searches from an experimentalist point of view. Emphasis is posed in the latest results and in the future perspectives. [ABSTRACT FROM AUTHOR]

The MINOS experiment uses the NuMI νμ beam to make precise measurements of neutrino flavor oscillations in the "atmospheric" neutrino sector. MINOS can also probe the yet-unknown neutrino mixing angle θ13 by searching for a νe appearance signal in the νμ beam. This paper reviews the techniques developed for the first νe appearance analysis in MINOS. [ABSTRACT FROM AUTHOR]

A brief review for particle physicists on the cosmological impact of neutrinos and on restrictions on neutrino properties from cosmology is given. The paper includes a discussion of upper bounds on neutrino mass and possible ways to relax them, methods to observe the cosmic-neutrino background, bounds on the cosmological lepton asymmetry which are strongly improved by neutrino oscillations, cosmological effects of breaking of the spin-statistics theorem for neutrinos, bounds on mixing parameters of active and possible sterile neutrinos with account of active-neutrino oscillations, bounds on right-handed currents and neutrino magnetic moments, and some more. [ABSTRACT FROM AUTHOR]

The main purpose of the Cryogenic Underground Observatory for Rare Events (CUORE) experiment is the search for the Neutrinoless Double Beta Decay (0νDBD) of 130Te reaching a sensitivity on Majorana mass better than 50 meV. Cuoricino represents not only the first stage of CUORE, but also the most massive 0νDBD experiment presently running. Present results and future planning of these experiments will be described in the paper. [ABSTRACT FROM AUTHOR]

The aim of these notes is to provide a brief review of the topic of neutrino astronomy and in particular of neutrinos from core collapse supernovae. They are addressed to a curious reader, beginning to work in a multidisciplinary area that involves experimental neutrino physics, astrophysics, nuclear physics and particle physics phenomenology. After an introduction to the methods and goals of neutrinos astronomy, we focus on core collapse supernovae, as (one of) the most promising astrophysical source of neutrinos. The first part is organized almost as a tale, the last part is a bit more technical. We discuss the impact of flavor oscillations on the supernova neutrino signal (=the change of perspective due to recent achievements) and consider one specific example of signal in detail. This shows that effects of oscillations are important, but astrophysical uncertainties should be thought as an essential systematics for a correct interpretation of future experimental data. Three appendices corroborate the text with further details and some basics on flavor oscillations; but no attempt at a complete bibliographical survey is made (in practice, we selected a few references that we believe are useful for a "modern" introduction to the subject and suggest the use of public databases for papers [e.g. SPIRES database http://www-spires.slac.stanford.edu/spires/hep/; NASA/ESO database http://esoads.eso.org/abstract service.html] and for experiments [see SPIRES in previous entry and the PaNAGIC site at http://www.lngs.infn.it/] for more complete information). [ABSTRACT FROM AUTHOR]

The double-beta decay process has been widely investigated in the last two decades due to the possible lepton number nonconservation decay modes that may occur. An experimental evidence of these modes would lead to the conclusion that neutrino is a massive Majorana particle. At present, when the nonzero neutrino mass is convincingly proved by neutrino oscillation experiments, the double-beta decay investigations are the most promising for determining the absolute value of the neutrino mass. In this paper we give a brief review of some recent nuclear double-beta decay investigations in connection with neutrino mass. We discuss the potential of this process to search for beyond standard model physics, the QRPA-based methods for computing the relevant nuclear matrix elements and the derivation of neutrino masses both from double-beta decay and neutrino oscillation data and in agreement with the present cosmological constraints. [ABSTRACT FROM AUTHOR]

This paper deals with a nucleus electromagnetically coupled with the bound states of its electronic surroundings. It describes the temperature dependence of its dynamics and the onset of potential Rabi oscillations by means of a Master Equation. The latter is generalized in order to account for possible strong resonances. Throughout the paper the approximation schemes are discussed and tested. To cite this article: J.-J. Niez, C. R. Physique 3 (2002) 1255–1261. [ABSTRACT FROM AUTHOR]

The oscillation neutrino problem in the extended standard model with minimal number of parameters is considered. The dispersion relations with explicit neutrino–antineutrino asymmetry are discussed and an explanation to the MINIBooNE and solar neutrino controversy is offered. Bounds for the CPT violation symmetry are also found. [ABSTRACT FROM AUTHOR]

Thermohydraulic phenomena of a steam-water natural-circulation (SWNC) system are very complicated, particularly, during its start-up and shutdown. Its performance strongly depends on the circulation inside it. Accurate quantification of the flow, void fraction, two-phase level, boiling boundary, etc., is difficult at both steady state and transient states like load variation, start-up, and shutdown. Attempts have been made to develop a high-fidelity thermohydraulic model (five-equation scheme) that caters to non-homogeneous and thermal nonequilibrium flow to derive the dynamic effect of heating rate on the performance of the SWNC loop of steam generator of an Indian nuclear reactor during steaming-up period. The proposed work also attempts to predict boiling height, flow reversal, and density-wave oscillation (DWO). The boiling channel of the SWNC loop is modeled based on the moving boundary analysis using finite volume method. In this moving boundary problem, both control volumes of single-phase zone and two-phase zone change with time. Numerical results have been presented in this paper The results indicate that both circulation flow variation and two-phase level variation in steam drum have strong dependency on void fraction in the boiling channel. Flow-reversal phenomenon is identified during the initial stage of boiling. Two-phase swelling and collapse that occur during the start-up are predicted. Above a critical heating rate, DWO has been observed. All these phenomena have been explained. [ABSTRACT FROM AUTHOR]

The observed phenomenon of neutrino oscillations is interpreted as the proof that neutrinos must have mass. As this is true for the neutrinos in the mass basis, the mass matrix in the flavor (weak) basis may still contain zeros. This can happen if the CP violating phases, usually neglected, come into play and result in suppression of processes which half-life depends on the masses of νe, νμ, or ντ. In the present paper we investigate the possibility of such suppression of the neutrinoless double beta decay (0ν2β). [ABSTRACT FROM AUTHOR]

In this paper we report the experimental observations of the effects of various surfactants on the oscillations of the ferroin-catalyzed Belousov−Zhabotinsky (BZ) reaction. The oscillations are followed by observing the change in absorbance at 510 nm due to ferroin in a well-stirred closed BZ reacting system. We have used sodium dodecyl sulfate (SDS) as the anionic surfactant, cetyl trimethylammonium bromide (CTAB) as the cationic surfactant, Triton X-100 as the neutral surfactant, and 3-[(3-cholamidopropyl)dimethylammonio)]-1-propanesulfonate (CHAPS) as the zwitterionic surfactant. In general, we observed that there is a change in the oscillation behavior in the presence of each of these surfactants above their critical micellar concentrations. For different surfactants, the time-dependent evolution of the oscillations is found to be characteristic of the surfactant. The results of our study suggest that the evolution of oscillations is most regular in the presence of micelles of SDS. [ABSTRACT FROM AUTHOR]

This paper discusses the oscillation physics that can be performed at a future neutrino factory. Different channels that are accessible are considered from the point of view of their physics potential and possible experimental issues. Few comments are made about neutrino superbeams. [Copyright &y& Elsevier]

We describe theory and implementation of oscillator strengths, orbital-relaxed first-order properties, and nuclear gradients for the local algebraic diagrammatic construction scheme through second order. The formalism is derived via time-dependent linear response theory based on a second-order unitary coupled cluster model. The implementation presented here is a modification of our previously developed algorithms for Laplace transform based local time-dependent coupled cluster linear response (CC2LR); the local approximations thus are state specific and adaptive. The symmetry of the Jacobian leads to considerable simplifications relative to the local CC2LR method; as a result, a gradient evaluation is about four times less expensive. Test calculations show that in geometry optimizations, usually very similar geometries are obtained as with the local CC2LR method (provided that a second-order method is applicable). As an exemplary application, we performed geometry optimizations on the low-lying singlet states of chlorophyllide a. [ABSTRACT FROM AUTHOR]

Line shape functions of a model system are analyzed, describing an oscillator carrying state coupled to background states randomly distributed in energy and with random coupling constants. Depending on the energy distribution functions or the nature of the coupling distribution, different line shape functions, such as the Lorentzian, the Fano, or that related to the nonexponential decay of the Förster type are recovered as limiting cases. Conditions for the range of applicability of a specially introduced mean square coupling approximation are derived. It is shown that the appearance of a Lorentzian line shape does not imply directly a homogeneous decay mechanism and that, on the other hand, commonly accepted conditions for the so-called statistical limit, expressed in terms of an average density and an average coupling, do not necessarily lead to a Lorentzian line shape. This is illustrated analytically through a model with randomly distributed transition dipolar couplings. Other applications relate to spectral diffusion in proteins and to bridged charge transfer. [ABSTRACT FROM AUTHOR]

In this paper, particle creation in curved space is studied from a mathematical perspective. In particular, particle production is calculated at a given time using the so-called instantaneous diagonalization method. As an application, we study particle production in a non-oscillating model where re-heating may be explained from the point of view of gravitational particle creation. To conclude the paper, we re-calculate, with all mathematical detail, particle production in the Starobinsky model. [ABSTRACT FROM AUTHOR]

In this work, we have explored the possibilities of improving CP violation (CPV) discovery potential of newly planned Long-Baseline Neutrino Experiment (LBNE), USA, by combining with data from reactors. The third mixing angle θ13 is now very precisely measured and this precise measurement of θ13 helps in the measurement of CPV. Here, CPV is studied with and without data from reactors. The impact of placing a neutrino data (ND) is also studied. It is found that CPV discovery potential of LBNE with ND increases when combined with data from reactors. With a far detector of 35 kt, it is possible to obtain 5σ sensitivity of CPV when run for 5 years in ν and 5 years in mode. When normal hierarchy is assumed, CPV sensitivity is maximum. CPV discovery is possible by combining 5 years neutrino data from LBNE with 3 years anti-neutrino data from reactors. This study reveals that CPV can also be discovered at 5σ cl in inverted mass hierarchy (IH) mode when appearance measurement of LBNE is combined with reactors. [ABSTRACT FROM AUTHOR]

In the present work, we discuss the effects of the inclusion of sterile-active neutrino oscillations during the production of primordial light-nuclei. We assume that the sterile neutrino mass-eigenstate might oscillate with the two lightest active neutrino mass-eigenstates, with mixing angles ϕ1 and ϕ2. We also allow a constant renormalization (represented by a parameter (ζ)) of the sterile neutrino occupation factor. Taking ζ and the mixing angles as free parameters, we have computed distribution functions of active and sterile neutrinos and primordial abundances. Using observable data we set constrains in the free parameters of the model. It is found that the data on primordial abundances are consistent with small mixing angles and with a value of ζ smaller than 0.65 at 3σ level. [ABSTRACT FROM AUTHOR]