Balancing protection and investment: structural reforms in five countries

Structural Reforms (SRs) are increasingly at the core of the European and national agenda. But what are SRs? And what are the main factors shaping their content? This analysis of the structural reforms adopted, between 2008 and 2015 in five European Union (EU) countries - the Czech Republic, Finland, Germany, Ireland and Italy - allows us to address these two questions. The book proposes a new definition of SRs, combining supply-side and more demand-side policy measures. An analysis of the five countries under scrutiny shows how a combination of EU constraints and opportunities, domestic path-dependency and political dynamics has resulted in different structural reform trends: while some countries have experienced an overall devaluation in social standards (e.g. Ireland), others have pursued more mixed strategies. What is more, SRs have gone through different periods. After a first phase of anti-cyclical measures, austerity dominated between 2011 and 2013. In more recent years, many countries have followed a more pro-growth strategy. The book provides evidence that the EU influenced SRs but lacked a coherent agenda to support growth. In such a context, different countries implemented different reform strategies, reflecting their (partly) diverging socio-economic models

Enhancement of three-mode optomechanical interaction by feedback-controlled light

We realise a feedback-controlled optical Fabry-Perot cavity in which the transmitted cavity output is used to modulate the input amplitude fluctuations. The resulting phase-dependent fluctuations of the in-loop optical field, which may be either sub-shot- or super-shot-noise, can be engineered to favorably affect the optomechanical interaction with a nanomechanical membrane placed within the cavity. Here we show that in the super-shot-noise regime ("anti-squashed light") the in-loop field has a strongly reduced effective cavity linewidth, corresponding to an increased optomechanical cooperativity. In this regime feedback improves the simultaneous resolved sideband cooling of two nearly degenerate membrane mechanical modes by one order of magnitude.Comment: 16 pages, 11 figure

Enhancing sideband cooling by feedback--controlled light

We realise a phase-sensitive closed-loop control scheme to engineer the fluctuations of the pump field which drives an optomechanical system, and show that the corresponding cooling dynamics can be significantly improved. In particular, operating in the counter-intuitive "anti-squashing" regime of positive feedback and increased field fluctuations, sideband cooling of a nanomechanical membrane within an optical cavity can be improved by 7.5~dB with respect to the case without feedback. Close to the quantum regime of reduced thermal noise, such feedback-controlled light would allow going well below the quantum backaction cooling limit

Normal--mode splitting in a weakly coupled optomechanical system

Normal--mode splitting is the most evident signature of strong coupling between two interacting subsystems. It occurs when two subsystems exchange energy between themselves faster than they dissipate it to the environment. Here we experimentally show that a weakly coupled optomechanical system at room temperature can manifest normal--mode splitting when the pump field fluctuations are anti-squashed by a phase-sensitive feedback loop operating close to its instability threshold. Under these conditions the optical cavity exhibits an effectively reduced decay rate, so that the system is effectively promoted to the strong coupling regime

Mapping the evolution of scientific fields

Despite the apparent cross-disciplinary interactions among scientific fields, a formal description of their evolution is lacking. Here we describe a novel approach to study the dynamics and evolution of scientific fields using a network-based analysis. We build an idea network consisting of American Physical Society Physics and Astronomy Classification Scheme (PACS) numbers as nodes representing scientific concepts. Two PACS numbers are linked if there exist publications that reference them simultaneously. We locate scientific fields using a community finding algorithm, and describe the time evolution of these fields over the course of 1985-2006. The communities we identify map to known scientific fields, and their age depends on their size and activity. We expect our approach to quantifying the evolution of ideas to be relevant for making predictions about the future of science and thus help to guide its development.Comment: v3: re-ran analysis with new noise parameter choice; 10 pages for main paper; 11 pages for suppl. inf

Tested by the Polycrisis: Reforming or Transforming the EU?

This thematic issue addresses the question: To what extent have the latest crises—the pandemic crisis and Russia’s war in Ukraine—triggered institutional and policy change in the EU? It contributes to the literature on the impact of crises on integration and the EU political system, presenting new research based on fresh theoretical insights, empirical data, or a combination of both. Theoretically, the contributions collected in the thematic issue explore whether the crises represent a critical juncture for the EU, leading to institutional and/or policy innovations or, rather, set in motion more incremental processes of adaptation. Empirically, all articles—some of which are qualitative, while others are quantitative—are based on original or new data. The first group of contributions deals with institutional change, focusing both on formal (i.e., treaty reform) and informal (i.e., codes of conduct) institutions. A second group moves the focus to policy change, looking at the impact of the Covid-19 pandemic on several policy areas and the energy crisis. Overall, the key lesson is that the EU can now manage and absorb new shocks quite effectively. At the same time, however, it does not promote ambitious and coherent political models or policy paradigms. Instead, it provides room for experimentation through patchwork-like strategies where old and new instruments and settings mix

Amplitude and phase noise in Two-membrane cavity optomechanics

Cavity optomechanics is a suitable field to explore quantum effects on macroscopic objects, and to develop quantum technologies applications. A perfect control on the laser noises is required to operate the system in such extreme conditions, necessary to reach the quantum regime. In this paper we consider a Fabry-Perot cavity, driven by two laser fields, with two partially reflective SiN membranes inside it. We describe the effects of amplitude and phase noise on the laser introducing two additional noise terms in the Langevin equations of the system's dynamics. Experimentally, we add an artificial source of noise on the laser. We calibrate the intensity of the noise we inject into the system, and we check the validity of the theoretical model. This procedure provides an accurate description of the effects of a noisy laser in the optomechanical setup, and it allows to quantify the amount of noise

Corrigendum: Bidirectional Hebbian Plasticity Induced by Low-Frequency Stimulation in Basal Dendrites of Rat Barrel Cortex Layer 5 Pyramidal Neurons

Peer reviewedPeer Reviewe