Sequential nonideal measurements of quantum oscillators: Statistical characterization with and without environmental coupling

A one-dimensional quantum oscillator is monitored by taking repeated position measurements. As a first con- tribution, it is shown that, under a quantum nondemolition measurement scheme applied to a system initially at the ground state, (i) the observed sequence of measurements (quantum tracks) corresponding to a single experiment converges to a limit point, and that (ii) the limit point is random over the ensemble of the experiments, being distributed as a zero-mean Gaussian random variable with a variance at most equal to the ground-state variance. As a second contribution, the richer scenario where the oscillator is coupled with a frozen (i.e., at the ground state) ensemble of independent quantum oscillators is considered. A sharply different behavior emerges: under the same measurement scheme, here we observe that the measurement sequences are essentially divergent. Such a rigorous statistical analysis of the sequential measurement process might be useful for characterizing the main quantities that are currently used for inference, manipulation, and monitoring of many quantum systems. Several interesting properties of the quantum tracks evolution, as well as of the associated (quantum) threshold crossing times, are discussed and the dependence upon the main system parameters (e.g., the choice of the measurement sampling time, the degree of interaction with the environment, the measurement device accuracy) is elucidated. At a more fundamental level, it is seen that, as an application of basic quantum mechanics principles, a sharp difference exists between the intrinsic randomness unavoidably present in any quantum system, and the extrinsic randomness arising from the environmental coupling, i.e., the randomness induced by an external source of disturbance.Comment: pages 16 Figures

Phenomenology of SIDIS unpolarized cross sections and azimuthal asymmetries

I review the phenomenology of unpolarized cross sections and azimuthal asymmetries in semi-inclusive deeply inelastic scattering (SIDIS). The general theoretical framework is presented and the validity of the Gaussian model is discussed. A brief account of the existing analyses is provided.Comment: 12 pages, 5 figures, invited talk at "Transversity 2011", Veli Losinj, Croati

A revised model of fluid transport optimization in Physarum polycephalum

Optimization of fluid transport in the slime mold Physarum polycephalum has been the subject of several modeling efforts in recent literature. Existing models assume that the tube adaptation mechanism in P. polycephalum's tubular network is controlled by the sheer amount of fluid flow through the tubes. We put forward the hypothesis that the controlling variable may instead be the flow's pressure gradient along the tube. We carry out the stability analysis of such a revised mathematical model for a parallel-edge network, proving that the revised model supports the global flow-optimizing behavior of the slime mold for a substantially wider class of response functions compared to previous models. Simulations also suggest that the same conclusion may be valid for arbitrary network topologies.Comment: To appear in Journal of Mathematical Biolog

Multiple solutions for a fractional pp-Laplacian equation with sign-changing potential

We use a variant of the fountain Theorem to prove the existence of infinitely many weak solutions for the following fractional p-Laplace equation (-\Delta)^{s}_{p}u+V(x)|u|^{p-2}u=f(x,u) in R^N, where $s \in (0,1)$,$p \geq 2$,$N \geq 2$, $(-\Delta)^{s}_{p}$ is the fractional $p$-Laplace operator, the nonlinearity f is $p$-superlinear at infinity and the potential V(x) is allowed to be sign-changing

Disintegration Through Law?

This is certainly not the most propitious time to publish a Journal on "Law and Integration". It is disintegration, not integration, that seems to be the dominant motive behind the contemporary events in Europe; it is the panacea offered to soothe the fears raised by the multiple crises which hold the present state of Europe in a tight grip; it is the invisible thread keeping together the anxieties which underlie the scholarly discussions about its future. It is not our task to determine the multifarious factors, of a social, political or cultural nature, which led to the current state of things. But the analysis of law as a possible disintegration factor would clearly be part of our brief. In all its aspects, the EU-Turkey Statement of 18 March 2016 on the large influx of migrants and asylum seekers in Greece seems to be exploiting the potentialities offered by international law as an alternative decision- making procedure within the EU legal system. This is not a completely unexplored road. The Brexit agreement, adopted by the Member States, acting within the European Council on 18 and 19 February 2016 equally seems to subvert the very mission of the founding treaties: to create an ever closer Union. Even with respect to this precedent, however, the EU-Turkey Statement seems to go one step further as it represents a visible example of the creeping modifications of the EU legal and political system, which almost inadvertently happens with the abdicant consent of the other political EU Institutions. This use of international instruments has the effect of disregarding the European institutional balance upon which the acquis européen has developed and which, with all its limits, constitutes the legacy of the first phase of the European integration. It may shift the centre of gravity to the Member States, the unmoved movers of the European legal universe. It may subdue the institutional pluralism, which has represented the hallmark of the political experience of the European integration, and create, instead, an institutional desert, where the political power is concentrated in the hand of the States acting through the European Council. It may mark the return to a Europe of sovereign States and the definite disappearance of the notion of a European public interest, of which we are in desperate need