Bound Sets Approach to Impulsive Floquet Problems for Vector Second-Order Differential Inclusions

In this paper, the existence and the localization of a solution of an impulsive vector multivalued second-order Floquet boundary value problem are investigated. The method used in the paper is based on the combination of a fixed point index technique with bound sets approach. At first, problems with upper-Carathéodory right-hand sides are investigated and it is shown afterwards how can the conditions be simplified in more regular case of upper semi-continuous right hand side. In this more regular case, the conditions ensuring the existence and the localization of a solution are put directly on the boundary of the considered bound set. This strict localization of the sufficient conditions is very significant since it allows some solutions to escape from the set of candidate solutions. In both cases, the C1-bounding functions with locally Lipschitzian gradients are considered at first and it is shown afterwards how the conditions change in case of C2-bounding functions. The paper concludes with an application of obtained results to Liénard-type equations and inclusions and the comparisons of our conclusions with the few results related to impulsive periodic and antiperiodic Liénard equations are obtained

Hybrid superconducting quantum magnetometer

A superconducting quantum magnetometer based on magnetic flux-driven modulation of the density of states of a proximized metallic nanowire is theoretically analyzed. With optimized geometrical and material parameters transfer functions up to a few mV/Phi_0 and intrinsic flux noise ~10^{-9}Phi_0 Hz^{-1/2} below 1 K are achievable. The opportunity to access single-spin detection joined with limited dissipation (of the order of ~ 10^{-14} W) make this magnetometer interesting for the investigation of the switching dynamics of molecules or individual magnetic nanoparticles.Comment: 6 pages, 6 color figures, added calculation of the Josephson current, published versio

Mild Solutions of Second-Order Semilinear Impulsive Differential Inclusions in Banach Spaces

In this paper, the existence of a mild solution to the Cauchy problem for impulsive semi-linear second-order differential inclusion in a Banach space is investigated in the case when the nonlinear term also depends on the first derivative. This purpose is achieved by combining the Kakutani fixed point theorem with the approximation solvability method and the weak topology. This combination enables obtaining the result under easily verifiable and not restrictive conditions on the impulsive terms, the cosine family generated by the linear operator and the right-hand side while avoiding any requirement for compactness. Firstly, the problems without impulses are investigated, and then their solutions are glued together to construct the solution to the impulsive problem step by step. The paper concludes with an application of the obtained results to the generalized telegraph equation with a Balakrishnan–Taylor-type damping term

The damped vibrating string equation on the positive half-line

In this paper, the existence of a solution to the problem describing the small vertical vibration of an elastic string on the positive half-line is investigated in the case when both viscous and material damping coefficients are present. The result is obtained by transforming the original partial differential equation into an appropriate abstract second-order ordinary differential equation in a suitable infinite dimensional space. The abstract problem is then studied using the combination of the Kakutani fixed point theorem together with the approximation solvability method and the weak topology. The applied procedure enables obtaining the existence result also for problems depending on the first derivative, without any strict compactness assumptions put on the right-hand side and on the fundamental system generated by the linear term. The paper ends by applying the obtained result to the studied mathematical model describing the small vertical vibration of an elastic string with a nonlinear Balakrishnan–Taylor-type damping term

Electronic implementations of Interaction-Free Measurements

Three different implementations of interaction-free measurements (IFMs) in solid-state nanodevices are discussed. The first one is based on a series of concatenated Mach-Zehnder interferometers, in analogy to optical-IFM setups. The second one consists of a single interferometer and concatenation is achieved in the time domain making use of a quantized electron emitter. The third implementation consists of an asymmetric Aharonov-Bohm ring. For all three cases we show that the presence of a dephasing source acting on one arm of the interferometer can be detected without degrading the coherence of the measured current. Electronic implementations of IFMs in nanoelectronics may play a fundamental role as very accurate and noninvasive measuring schemes for quantum devices.Comment: 12 pages, 10 figure

Strictly localized bounding functions and Floquet boundary value problems

Semilinear multivalued equations are considered, in separable Banach spaces with the Radon-Nikodym property. An effective criterion for the existence of solutions to the associated Floquet boundary value problem is showed. Its proof is obtained combining a continuation principle with a Liapunov-like technique and a Scorza-Dragoni type theorem. A strictly localized transversality condition is assumed. The employed method enables to localize the solution values in a not necessarily invariant set; it allows also to introduce nonlinearities with superlinear growth in the state variable