On essential self-adjointness for magnetic Schroedinger and Pauli operators on the unit disc in R^2

We study the question of magnetic confinement of quantum particles on the unit disk \ID in \IR^2, i.e. we wish to achieve confinement solely by means of the growth of the magnetic field $B(\vec x)$ near the boundary of the disk. In the spinless case we show that $B(\vec x)\ge \frac{\sqrt 3}{2}\cdot\frac{1}{(1-r)^2}-\frac{1}{\sqrt 3}\frac{1}{(1-r)^2\ln \frac{1}{1-r}}$, for $|\vec x|$ close to 1, insures the confinement provided we assume that the non-radially symmetric part of the magnetic field is not very singular near the boundary. Both constants $\frac{\sqrt 3}{2}$ and $-\frac{1}{\sqrt 3}$ are optimal. This answers, in this context, an open question from Y. Colin de Verdi\`ere and F. Truc. We also derive growth conditions for radially symmetric magnetic fields which lead to confinement of spin 1/2 particles.Comment: 18 pages; the main theorem has been expanded and generalize

New features of some proton-neutron collective states

Using a schematic solvable many-body Hamiltonian, one studies a new type of proton-neutron excitations within a time dependent variational approach. Classical equations of motion are linearized and subsequently solved analytically. The harmonic state energy is compared with the energy of the first excited state provided by diagonalization as well as with the energies obtained by a renormalized RPA and a boson expansion procedure. The new collective mode describes a wobbling motion, in the space of isospin, and collapses for a particle-particle interaction strength which is much larger than the physical value. A suggestion for the description of the system in the second nuclear phase is made. We identified the transition operators which might excite the new mode from the ground state.Comment: 28 pages and 3 figure

Risks and Assets: A Qualitative Study of a Software Ecosystem in the Mining Industry

Digitalization and servitization are impacting many domains, including the mining industry. As the equipment becomes connected and technical infrastructure evolves, business models and risk management need to adapt. In this paper, we present a study on how changes in asset and risk distribution are evolving for the actors in a software ecosystem (SECO) and system-of-systems (SoS) around a mining operation. We have performed a survey to understand how Service Level Agreements (SLAs) -- a common mechanism for managing risk -- are used in other domains. Furthermore, we have performed a focus group study with companies. There is an overall trend in the mining industry to move the investment cost (CAPEX) from the mining operator to the vendors. Hence, the mining operator instead leases the equipment (as operational expense, OPEX) or even acquires a service. This change in business model impacts operation, as knowledge is moved from the mining operator to the suppliers. Furthermore, as the infrastructure becomes more complex, this implies that the mining operator is more and more reliant on the suppliers for the operation and maintenance. As this change is still in an early stage, there is no formalized risk management, e.g. through SLAs, in place. Rather, at present, the companies in the ecosystem rely more on trust and the incentives created by the promise of mutual future benefits of innovation activities. We believe there is a need to better understand how to manage risk in SECO as it is established and evolves. At the same time, in a SECO, the focus is on cooperation and innovation, the companies do not have incentives to address this unless there is an incident. Therefore, industry need, we believe, help in systematically understanding risk and defining quality aspects such as reliability and performance in the new business environment

Critical Space Infrastructure: A Complex System Governance Perspective

This paper examines the applicability of Complex System Governance (CSG) to advance the Critical Space Infrastructure field (CSI). CSI encompasses space related hardware, workforce, environment, facilities, and businesses that are necessary for societal well-being. CSI is increasing in importance as more societal serving systems are becoming dependent on CSI to operate. Given this increasing dependence on CSI, societal sectors are increasingly at risk should something go wrong with CSI upon which they depend. CSI has been developing is a fragmented way and lacks coherent organization. CSG is focused on design, execution, and evolution of system functions that provide for communications, control, coordination, and integration of complex systems. CSG provides structure and order to complex systems through a rigorous grounding in systems theory (the axioms and propositions that govern behavior, performance, and structure of complex systems), management cybernetics (the science of organizational structure), and system governance (focused on provision of direction, oversight, and accountability). In this paper the intersection of CSI and CSG is explored with respect to the value that can accrue to both fields through their intersection and joint development. The opportunities that lie at the intersection of these fields are examined. This paper concludes the exploration with a discussion of the implications for movement forward in bringing the value offered by CSG to the governance of space-based critical infrastructures