Electoral Systems in Context: Italy

Italy stands out among advanced industrialized democracies because of its frequency of major electoral reforms. In the postwar period, Italy has experienced four major electoral systems: the proportional representation (PR) system of the First Republic (1948–1992), mixed-member majoritarian (MMM, 1993–2005), and two varieties of PR with majority bonus (2005–2015, 2015–). In addition, there have been many failed attempts at electoral reform through legislation or referendum. The frequency of electoral reform makes Italy an important case for investigating the causes and effects of electoral system change. However, the path to each change has been somewhat idiosyncratic: the major reform of 1993 came against the backdrop of revelations of massive corruption, while the 2005 reform can be understood as an attempt to engineer divided government by an incumbent coalition expecting losses in the next election. The effects of the electoral reforms have also not always been as expected

Presidentialisation: One Term, Two Uses – Between Deductive Exercise and Grand Historical Narrative

This article focuses on the two main contributions to the contemporary academic debate about the term ‘presidentialisation’, namely the books by Samuels and Shugart and Poguntke and Webb. The aim is not to rehearse critiques that have already been made about this term or to add another to the list. Instead, the aim is to distinguish between two different ways in which the same term has been applied in the two studies. Both sets of authors are concerned with the same term, but each operationalises it in a different way. Acknowledging these differences allows us to focus on a specific aspect of Poguntke and Webb’s account that is absent from Samuels and Shugart’s, namely the construction of a grand historical narrative

When the powerful drag their feet

We examine the timing of group decisions that are taken by weighted voting. Decision-making is in two stages. In the second stage, players vote on a policy restriction. In the first stage, players vote to determine the timing of the second-stage decision: “early”, before players’ types are revealed, or “late”. Players differ in both size and voting power. We show that players with greater power tend to prefer a late vote, whereas less powerful players tend to want to vote early. By contrast, large players tend to prefer an early vote and small players a late vote. We present evidence from the literatures on corporate governance, international relations, European Union governance, and oil extraction. We examine an extension in which players choose the qualified majority threshold besides the timing of the second-stage vote

May a dissipative environment be beneficial for quantum annealing?

We discuss the quantum annealing of the fully-connected ferromagnetic $p$-spin model in a dissipative environment at low temperature. This model, in the large $p$ limit, encodes in its ground state the solution to the Grover's problem of searching in unsorted databases. In the framework of the quantum circuit model, a quantum algorithm is known for this task, providing a quadratic speed-up with respect to its best classical counterpart. This improvement is not recovered in adiabatic quantum computation for an isolated quantum processor. We analyze the same problem in the presence of a low-temperature reservoir, using a Markovian quantum master equation in Lindblad form, and we show that a thermal enhancement is achieved in the presence of a zero temperature environment moderately coupled to the quantum annealer.Comment: 4 pages, 1 figure, proceeding of IQIS 201

An eclectic political scientist. A tribute to Robert Elgie

Robert Elgie's contribution to comparative politics is considerable. His work covers a range of areas, including the study of political institutions, French politics, political leadership, presidentialism, semi-presidentialism and democratic transition. He became the leading scholar on semi-presidentialism and indeed defined much of the research agenda in this subfield. Last but not least, Elgie dealt with the definition, redefinition and measurement of new concepts in political science. He provided innovative and ground-breaking analyses of presidential power, as well as divided government, and presidentialization

Quantum annealing and advanced optimization strategies of closed and open quantum systems

Adiabatic quantum computation and quantum annealing are powerful methods designed to solve optimization problems more efficiently than classical computers. The idea is to encode the solution to the optimization problem into the ground state of an Ising Hamiltonian, which can be hard to diagonalize exactly and can involve long-range and multiple-body interactions. The adiabatic theorem of quantum mechanics is exploited to drive a quantum system towards the target ground state. More precisely, the evolution starts from the ground state of a transverse field Hamiltonian, providing the quantum fluctuations needed for quantum tunneling between trial solution states. The Hamiltonian is slowly changed to target the Ising Hamiltonian of interest. If this evolution is infinitely slow, the system is guaranteed to stay in its ground state. Hence, at the end of the dynamics, the state can be measured, yielding the solution to the problem. In real devices, such as in the D-Wave quantum annealers, the evolution lasts a finite amount of time, which gives rise to Landau-Zener diabatic transitions, and occurs in the presence of an environment, inducing thermal excitations outside the ground state. Both these limitations have to be carefully addressed in order to understand the true potential of these devices. The present thesis aims to find strategies to overcome these limitations. In the first part of this work, we address the effects of dissipation. We show that a low-temperature Markovian environment can improve quantum annealing, compared with the closed-system case, supporting other previous results known in the literature as thermally-assisted quantum annealing. In the second part, we combine dissipation with advanced annealing schedules, featuring pauses and iterated or adiabatic reverse annealing, which, in combination with low-temperature environments, can favor relaxation to the ground state and improve quantum annealing compared to the standard algorithm. In general, however, dissipation is detrimental for quantum annealing especially when the annealing time is longer than the typical thermal relaxation and decoherence time scales. For this reason, it is essential to devise shortcuts to adiabaticity so as to reach the adiabatic limit for relatively short times in order to decrease the impact of thermal noise on the performances of QA. To this end, in the last part of this thesis we study the counterdiabatic driving approach to QA. In counterdiabatic driving, a new term is added to the Hamiltonian to suppress Landau-Zener transitions and achieve adiabaticity for any finite sweep rate. Although the counterdiabatic potential is nonlocal and hardly implementable on quantum devices, we can obtain approximate potentials that dramatically enhance the success probability of short-time quantum annealing following a variational formulation

The process of democratisation, the political parties and the electoral systems in the Western Balkans (1990–2020)

At the end of the twentieth century, the transition from non-democratic regimes has been the most important political event in the Western Balkans. The fall of the Berlin wall in 1989 paved the way to the sudden collapse and breakdown of the communist regimes in Eastern Europe and in the Western Balkans, albeit some of them did already show a growing decline. Despite the variation in terms of institutional framework and electoral systems, the Western Balkan countries do present difference in some aspects of the political system but not for all the variables considered. The different scenarios that involved the Western Balkan countries during the armed conflicts have generated often negative outcomes in terms of democratic performances, or better have exacerbated persistent resistances to the democratic strengthening from the political actors. The factors beyond these different patterns can be indicated in three main areas: (1) the type of democratic transition and the role of the different actors in the process, (2) the influence of the political parties and their genetic features and (3) finally, considering the context, the impact of the war in the country