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We consider the Cauchy problem of a third order in time nonlinear equation known as the Jordan–Moore–Gibson–Thompson (JMGT) equation arising in acoustics as an alternative model to the well-known Kuznetsov equation. We show a local existence result in appropriate function spaces, and, using the energy method together with a bootstrap argument, we prove a global existence result for small data, without using the linear decay. Finally, polynomial decay rates in time for a norm related to the solution will be obtained. [ABSTRACT FROM AUTHOR]

In this work, explicit expressions for the transition rates of an isotropic quantum charged harmonic oscillator in the vicinity of a perfectly conducting half-space under the influence of an external classical source are obtained. In the absence of external sources, it is shown that the decay rate of an initially exited state of the oscillator is a periodic function in terms of the normalized distance to the plate. The modified transition rates in the presence of external classical sources are obtained in the large-time limit indicating a contribution proportional to the squared module of the Fourier transform of the external source. In the absence of the conducting plate and external sources, the results are in agreement with the free space case. The problem is generalized to the case of a real conducting half-space. [ABSTRACT FROM AUTHOR]

In this work, we demonstrate and evaluate the viability of SrAl2O4:Eu 2 + , Dy 3 + crystals for long-term light storage applications at low temperatures that can be activated at higher temperatures for on-demand lighting applications. The switching mechanism is discussed from the point of view of the possible interplay between charge transport and the persistent luminescence in this system. Step-wise temperature-dependent luminescence decay time measurement is carried out to determine the optimal temperature for photo-charging and the operational temperature limit of the crystal-under-test as light sources. [ABSTRACT FROM AUTHOR]

A dynamical model is employed to determine some peculiar properties of the scission neutrons, i.e., those emitted at the rupture of the neck between the fragments during low energy nuclear fission. Thus, by a specially adapted procedure, we calculate the time-dependent decay rate. This, defines the character of the emission process: pulsed or exponentially. From the time dependence of the survival probability, we deduced the "half-life" of the scission neutron emission. The angular distribution of the scission neutrons with respect to the fission axis is calculated as well. This is obtained for sets of neutron wave functions defined by a given quantum number Ω (projection of the total angular momentum on the symmetry axis). A strong dependence on Ω was found, namely, wave functions with different Ω have different most probable emission angles: from emission along the fission axis (1/2) to emission perpendicular to the fission axis (9/2). This result leads to a new interpretation of the measured angular distribution of the prompt fission neutrons. Finally, an extension of the dynamical model (i.e., with a time-dependent potential also after scission) is presented. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the decay properties of the Bresse-Cattaneo system in the whole space. We show that the coupling of the Bresse system with the heat conduction of the Cattaneo theory leads to a loss of regularity of the solution and we prove that the decay rate of the solution is very slow. In fact, we show that the -norm of the solution decays with the rate of . The behavior of solutions depends on a certain number (which is the same stability number for the Timoshenko-Cattaneo system [Damping by heat conduction in the Timoshenko system: Fourier and Cattaneo are the same, J. Differential Equations 255(4) (2013) 611-632; The stability number of the Timoshenko system with second sound, J. Differential Equations 253(9) (2012) 2715-2733]) which is a function of the parameters of the system. In addition, we show that we obtain the same decay rate as the one of the solution for the Bresse-Fourier model [The Bresse system in thermoelasticity, to appear in Math. Methods Appl. Sci.]. [ABSTRACT FROM AUTHOR]

This paper is devoted to the study of a nonlinear coupled system of two Korteweg-de Vries equations in a periodic domain under the effect of an internal damping term. The system was introduced by Gear and Grimshaw to model the interactions of two-dimensional, long, internal gravity waves propagation in a stratified fluid. Designing a time-varying feedback law and using a Lyapunov approach, we establish the exponential stability of the solutions in Sobolev spaces of any positive integral order. [ABSTRACT FROM AUTHOR]

The 8Be nucleus decays into two 4He nuclei. This decay constant is theoretically estimated using Fermi golden rule and the ground state wave functions of the 4He and 8Be nuclei. The estimated result agrees pretty well with the reported experimental value. [ABSTRACT FROM AUTHOR]

The Lyapunov exponent gives a measure of the mean decay/growth rates of the flows of nonlinear systems. However, the Lyapunov exponent needs an infinite time interval of flows and the Jacobian matrix of system dynamics. In this paper, we propose an instantaneous decay/growth rate that is a kind of generalized Lyapunov exponent and call the instantaneous Lyapunov exponent (ILE) with respect to a decay function. The instantaneous Lyapunov exponent is one of the measures that estimate the decay and growth rates of flows of nonlinear systems by assigning a comparison function and can apply a stable system whose decay rate is slower than an exponential function. Moreover, we propose a synchronization measure of two signals using the ILE. [ABSTRACT FROM AUTHOR]

We consider a class of second-order hyperbolic systems which describe viscoelastic materials, and we extend the recent results by Dharmawardane and Conti et al. More precisely, for all initial data (u0, u1)∈(Hs+1(ℝN) ∩ L1, γ(ℝN))×(Hs(ℝN) ∩ L1, γ(ℝN)) with γ∈[0, 1], we derive faster decay estimates for both dissipative structure or regularity-loss type models. To this end, we first transform our problem into Fourier space and then, by using the pointwise estimate derived by Dharmawardane et al., combined with a device to treat the Fourier transform in the low frequency region, we derive optimal decay results for the solutions to our problem. Finally, we use these decay estimates for the linear problem, combined with the weighted energy method introduced by Todorova and Yordanov, and tackle a semilinear problem. [ABSTRACT FROM AUTHOR]

The spacecraft attitude control systems are becoming more and more sophisticated with the increasing complex system configurations. This paper investigates the problem of three-axis rigid spacecraft maneuver control. The rigid spacecraft model consisting of the dynamic and kinematics equation is firstly provided. This nonlinear model is converted into a Takagi-Sugeno fuzzy model. Then, based on the parallel distributed compensation scheme, a fuzzy state feedback controller is designed for the obtained T-S fuzzy model with considering the decay rate and input constraints. Next, sufficient conditions for the existence of such a controller are derived in terms of linear matrix inequalities and the controller design is cast into a convex optimization problem subject to linear matrix inequalities constraints, which can be readily solved via Matlab LMI toolbox. At last, a design example shows that the time of spacecraft attitude maneuver is shortened and the input constraint is realized. The simulation results show the effectiveness of the proposed methods. [ABSTRACT FROM AUTHOR]

Quantum properties of a (1+1)-dimensional scalar theory on a cylinder with a compact spatial part, namely, 0 ≤ x ≤ L, are considered. In particular, quantum theory around the classical periodic field configurations is studied and the lifetime of a quantum periodic instanton is estimated. [ABSTRACT FROM AUTHOR]

In a mediator, query usage should be carefully monitored to determine the optimized set of materialized sub-queries, since the integration schema of a mediator can be incrementally modified and the evaluation frequency of a global query can also be continuously varied. This paper proposes a theoretical basis for adaptive selection of materialized sub-queries such that available storage in a mediator can be highly utilized at any time. In order to differentiate the recent usage of a query from the past, the accumulated usage frequency of a query decays as time goes by. Consequently, it is possible to find the optimum set of materialized sub-queries which minimizes the total evaluation cost of global queries in linear search complexity. [ABSTRACT FROM AUTHOR]

We provide a conceptual unified description of the quantum properties of black holes (BH), elementary particles, de Sitter (dS) and Anti-de Sitter (AdS) string states.The conducting line of argument is the classical–quantum (de Broglie, Compton) duality here extended to the quantum gravity (string) regime (wave–particle–string duality). The semiclassical (QFT) and quantum (string) gravity regimes are respectively characterized and related: sizes, masses, accelerations and temperatures. The Hawking temperature, elementary particle and string temperatures are shown to be the same concept in different energy regimes and turn out the precise classical–quantum duals of each other; similarly, this result holds for the BH decay rate, heavy particle and string decay rates; BH evaporation ends as quantum string decay into pure (nonmixed) radiation. Microscopic density of states and entropies in the two (semiclassical and quantum) gravity regimes are derived and related, an unifying formula for BH, dS and AdS states is provided in the two regimes. A string phase transition towards the dS string temperature (which is shown to be the precise quantum dual of the semiclassical (Hawking–Gibbons) dS temperature) is found and characterized; such phase transition does not occurs in AdS alone. High string masses (temperatures) show a further (square root temperature behavior) sector in AdS. From the string mass spectrum and string density of states in curved backgrounds, quantum properties of the backgrounds themselves are extracted and the quantum mass spectrum of BH, dS and AdS radii obtained. [ABSTRACT FROM AUTHOR]

We present preliminary results of maximum-likelihood Dalitz plot analyses performed by the BABAR Collaboration of the charmless hadronic decays B0 → K+π-π0, B+ → K+π-π+, and B+ → π+π-π+. We report inclusive decay rates, as well as fractions and phases for intermediate resonant decays. We also report CP-violating charge asymmetries for intermediate resonant decays of neutral B mesons. [ABSTRACT FROM AUTHOR]