Reservoir engineering of a mechanical resonator: generating a macroscopic superposition state and monitoring its decoherence

A deterministic scheme for generating a macroscopic superposition state of a nanomechanical resonator is proposed. The nonclassical state is generated through a suitably engineered dissipative dynamics exploiting the optomechanical quadratic interaction with a bichromatically driven optical cavity mode. The resulting driven dissipative dynamics can be employed for monitoring and testing the decoherence processes affecting the nanomechanical resonator under controlled conditions.Comment: 10 pages, 7 figure

Suppression of Stokes scattering and improved optomechanical cooling with squeezed light

We develop a theory of optomechanical cooling with a squeezed input light field. We show that Stokes heating transitions can be \emph{fully} suppressed when the driving field is squeezed below the vacuum noise level at an appropriately selected squeezing phase and for a finite amount of squeezing. The quantum backaction limit to laser cooling can be therefore moved down to zero and the resulting final temperature is then solely determined by the ratio between the thermal phonon number and the optomechanical cooperativity parameter, independently of the actual values of the cavity linewidth and mechanical frequency. Therefore driving with a squeezed input field allows to prepare nanomechanical resonators, even with low resonance frequency, in their quantum ground state with a fidelity very close to one

Modeling Growth, Distribution, and the Environment in a Stock-Flow Consistent Framework. Policy Paper no 18

Economic policy in the EU faces a trilemma of solving three challenges simultaneously - growth, distribution, and the environment. In order to assess policies that address these issues simultaneously, economic models need to account for both sector-sector and sector-environment feedbacks within a single framework.This paper presents a multi-sectoral stock-flow consistent (SFC) macro model where a demand-driven economy consisting of multiple institutional sectors - firms, energy, households, government, and financial - interacts with the environment. The model is calibrated for the EU region and five policy scenarios are evaluated; low consumption, a capital stock damage function, carbon taxes, higher share of renewable energy, and technological shocks to productivity. Policy outcomes are tracked on overall output, unemployment, income and income distributions, energy, and emission levels. Results show that investment in mitigation technologies allows for absolute decoupling and ensures that the above three issues can be solved simultaneously.Series: WWWforEurop

Prospects of reinforcement learning for the simultaneous damping of many mechanical modes

We apply adaptive feedback for the partial refrigeration of a mechanical resonator, i.e. with the aim to simultaneously cool the classical thermal motion of more than one vibrational degree of freedom. The feedback is obtained from a neural network parametrized policy trained via a reinforcement learning strategy to choose the correct sequence of actions from a finite set in order to simultaneously reduce the energy of many modes of vibration. The actions are realized either as optical modulations of the spring constants in the so-called quadratic optomechanical coupling regime or as radiation pressure induced momentum kicks in the linear coupling regime. As a proof of principle we numerically illustrate efficient simultaneous cooling of four independent modes with an overall strong reduction of the total system temperature.Comment: Machine learning in Optomechanics: coolin

Reflecting Disaster Risk in Development Indicators

Disasters triggered by hazards, such as floods, earthquakes, droughts, and cyclones, pose significant impediments to sustainable development efforts in the most vulnerable and exposed countries. Mainstreaming disaster risk is hence seen as an important global agenda as reflected in the Sustainable Development Goals (SDGs) and the Sendai Framework for Disaster Risk Reduction (SFDRR) 2015-2030. Yet, conventional development indicators remain largely negligent of the potential setbacks that may be posed by disaster risk. This article discusses the need to reflect disaster risk in development indicators and proposes a concept disaster risk-adjusted human development index (RHDI) as an example. Globally available national-level datasets of disaster risk to public and private assets (including health, educational facilities, and private housing) is combined with an estimate of expenditure on health, education, and capital formation to construct an RHDI. The RHDI is then analyzed across various regions and HDI groups, and contrasted with other HDI variants including inequality-adjusted HDI (IHDI) and the gender-specific female HDI (FHDI) to identify groups of countries where transformational disaster risk reduction (DRR) approaches may be necessary

Family Business Groups and Tunneling Framework : Application and Evidence from Pakistan

In Pakistan there is a ubiquity of firms in which there exists a controlling shareholder, usually in the form of the family. By and large this control is maintained via crossshareholding and inter-locked directorships which in turn is facilitated by the pyramidal organization of these firms. Moreover, these controlling families have often been alleged of tunneling resources from firms in which they have few cash flow rights to ones in which they have more cash flow rights. This paper attempts to quantify the extent of tunneling prevalent in Pakistani family business groups. The framework that is adopted is one that has been presented by Mullainathan et al. (2000) : we use the responses of different firms to performance shocks and map out the flow of resources within a group of firms to quantify the extent to which the marginal rupee is tunneled. We apply this technique to data on Pakistan business groups.Pakistan, tunneling, business groups, crossshareholding