Towards formal models and languages for verifiable Multi-Robot Systems

Incorrect operations of a Multi-Robot System (MRS) may not only lead to unsatisfactory results, but can also cause economic losses and threats to safety. These threats may not always be apparent, since they may arise as unforeseen consequences of the interactions between elements of the system. This call for tools and techniques that can help in providing guarantees about MRSs behaviour. We think that, whenever possible, these guarantees should be backed up by formal proofs to complement traditional approaches based on testing and simulation. We believe that tailored linguistic support to specify MRSs is a major step towards this goal. In particular, reducing the gap between typical features of an MRS and the level of abstraction of the linguistic primitives would simplify both the specification of these systems and the verification of their properties. In this work, we review different agent-oriented languages and their features; we then consider a selection of case studies of interest and implement them useing the surveyed languages. We also evaluate and compare effectiveness of the proposed solution, considering, in particular, easiness of expressing non-trivial behaviour.Comment: Changed formattin

Importance Sampling Scheme for the Stochastic Simulation of Quantum Spin Dynamics

The numerical simulation of dynamical phenomena in interacting quantum systems is a notoriously hard problem. Although a number of promising numerical methods exist, they often have limited applicability due to the growth of entanglement or the presence of the so-called sign problem. In this work, we develop an importance sampling scheme for the simulation of quantum spin dynamics, building on a recent approach mapping quantum spin systems to classical stochastic processes. The importance sampling scheme is based on identifying the classical trajectory that yields the largest contribution to a given quantum observable. An exact transformation is then carried out to preferentially sample trajectories that are close to the dominant one. We demonstrate that this approach is capable of reducing the temporal growth of fluctuations in the stochastic quantities, thus extending the range of accessible times and system sizes compared to direct sampling. We discuss advantages and limitations of the proposed approach, outlining directions for further developments.Comment: Submission to SciPost, v2; 9 + 2 pages, 5 figure

The Future Concept of Work

This chapter offers a reappraisal of the idea of ‘personal work’ and a critical assessment of the concept of subordination, which shapes the traditional contract of employment and subordinate work. The authors suggest that the notion of personal work may be more useful in attempts to develop a newly conceptualised concept of human labour, one capable of incorporating certain dimensions of (unpaid) gendered labour, ‘heteromated’ labour (‘heteromation’ is the extraction of economic value from low-cost or free labour in computer-mediated networks), and other forms of socially (and ecologically) valuable labour that hitherto have been excluded from the realm of formal, protected and paid employment

“Lifting the Private-Law Veil”: Employer Authority and the “Contractual-Coating” of Worker Subordination

Despite the notion of subordination in work relations and the subjection of workers to the managerial prerogatives of employers have received significant consideration and discourse since the outset of labour law, critical examinations of the underlying foundations of such subordination and subjection in contemporary democracies founded on the rule of law remain scarce. This article wants to prompt a novel reflection on these issues, starting with a historical analysis of their origins and a renewed understanding of their legal background. It opens by discussing some outstanding issues concerning work subordination that are not adequately captured by the classic theory of the firm. It argues that the free nature of the individual negotiation of work arrangements at the dawn of industrialisation must be called into question from a legal perspective and highlights how disciplinary approaches to societies and work have materially shaped those arrangements. It then discusses the historical foundations of employer authority and worker subordination in what evolved into the modern contract of employment in various jurisdictions. It contends that, despite this authority and subordination being “coated” in contractual and private-law guises to make them acceptable for the public discourse, their origins are rooted in public law and action, sometimes with overtly authoritarian aims. It, then, argues that acknowledging the public origins of employer powers should prompt an intensified scrutiny of employer choices beyond what courts are ready to do for managerial conduct that falls short of meeting standards for harassment, constructive dismissal or resignation for cause. It concludes by outlining potential avenues for future research on how the “personal work approach” may offer insights into questioning worker subordination in contemporary democratic societies. This article is forthcoming in a special issue of the Comparative Labor Law & Policy Journal titled New Perspectives on Worker Subordination , edited by Valerio De Stefano, Sara Slinn, and Eric Tucker

Beyond the random phase approximation with a local exchange vertex

With the aim of constructing an electronic structure approach that systematically goes beyond the GW and random phase approximation (RPA) we introduce a vertex correction based on the exact-exchange (EXX) potential of time-dependent density functional theory. The EXX vertex function is constrained to be local but is expected to capture similar physics as the Hartree-Fock vertex. With the EXX vertex, we then unify different beyond-RPA approaches such as the various resummations of RPA with exchange and the second-order screened exchange approximation. The theoretical analysis is supported by numerical studies on the hydrogen dimer and the electron gas, and we discuss the role of including the vertex correction in both the screened interaction and the self-energy. Finally, we give details on our implementation within the plane-wave pseudo potential framework and demonstrate the excellent performance of the different RPA with exchange methods in describing the energetics of hydrogen and van der Waals bonds

The fundamental relation between supermassive black holes and their host galaxies

We study the correlations between supermassive black holes (BHs) and their host galaxies, using a sample of 83 BH masses collected from the most recent and reliable spatially resolved estimates available from the literature. We confirm the mono- and bivariate correlations between SMBHs and the bulges of their host galaxies, confirming that the correlation with the effective velocity dispersion is not significantly improved by higher dimensionality. Instead, pseudo-bulges do not seem to correlate with their SMBHs, probably because their secular evolution is often unable to trigger accretion onto the central BH. We then present a novel approach aimed at finding the fundamental relation between SMBHs and their host galaxies. For the first time, we analytically combine BH masses with the Fundamental Plane (FP), showing that M_(BH)–σ_e appears to be the fundamental relation rather than a putative ‘BH Fundamental Plane’ of the kind M_(BH)–σ_e–R_e. These results can be explained by a picture which sees the M_(BH)–σ_e relation as a natural outcome of the change in AGN feedback from momentum-driven to energy-driven. The other scaling relations are then established through the FP

The Fundamental Relation between Supermassive Black Holes and Their Host Galaxies

We study the correlations between Supermassive Black Holes (BH) and their host galaxies, using a sample of 83 BH masses collected from the most recent and reliable spatially resolved estimates available from the literature. We confirm the mono- and bivariate correlations between SMBHs and the bulges of their host galaxies, confirming that the correlation with the effective velocity dispersion is not significantly improved by higher dimensionality. Instead, pseudobulges do not seem to correlate with their SMBHs, probably because their secular evolution is often unable to trigger accretion onto the central BH. We then present a novel approach aimed at finding the fundamental relation between SMBHs and their host galaxies. For the first time, we analytically combine BH masses with the Fundamental Plane (FP), showing that Mbh-sigma_e appears to be the fundamental relation rather than a putative "BH Fundamental Plane" of the kind Mbh-sigma_e-R_e. These results can be explained by a picture which sees the Mbh-sigma_e relation as a natural outcome of the change in AGN feedback from momentum- to energy-driven. The other scaling relations are then established through the FP.Comment: 15 pages, 11 figures, accepted by MNRA