Electromechanical Quantum Simulators

Digital quantum simulators are among the most appealing applications of a quantum computer. Here we propose a universal, scalable, and integrated quantum computing platform based on tunable nonlinear electromechanical nano-oscillators. It is shown that very high operational fidelities for single and two qubits gates can be achieved in a minimal architecture, where qubits are encoded in the anharmonic vibrational modes of mechanical nanoresonators, whose effective coupling is mediated by virtual fluctuations of an intermediate superconducting artificial atom. An effective scheme to induce large single-phonon nonlinearities in nano-electromechanical devices is explicitly discussed, thus opening the route to experimental investigation in this direction. Finally, we explicitly show the very high fidelities that can be reached for the digital quantum simulation of model Hamiltonians, by using realistic experimental parameters in state-of-the art devices, and considering the transverse field Ising model as a paradigmatic example.Comment: 14 pages, 8 figure

Optimized Confinement of Fermions in Two Dimensions

One of the challenging features of studying model Hamiltonians with cold atoms in optical lattices is the presence of spatial inhomogeneities induced by the confining potential, which results in the coexistence of different phases. This paper presents Quantum Monte Carlo results comparing meth- ods for confining fermions in two dimensions, including conventional diagonal confinement (DC), a recently proposed 'off-diagonal confinement' (ODC), as well as a trap which produces uniform den- sity in the lattice. At constant entropy and for currently accessible temperatures, we show that the current DC method results in the strongest magnetic signature, primarily because of its judicious use of entropy sinks at the lattice edge. For d-wave pairing, we show that a constant density trap has the more robust signal and that ODC can implement a constant density profile. This feature is important to any prospective search for superconductivity in optical lattices

Magnetism and pairing of two-dimensional trapped fermions

The emergence of local phases in a trapped two-component Fermi gas in an optical lattice is studied using quantum Monte Carlo simulations. We treat temperatures that are comparable or lower than those presently achievable in experiments and large enough systems that both magnetic and paired phases can be detected by inspection of the behavior of suitable short-range correlations. We use the latter to suggest the interaction strength and temperature range at which experimental observation of incipient magnetism and d-wave pairing are more likely and evaluate the relation between entropy and temperature in two-dimensional confined fermionic systems.Comment: 4 pages + supplementary materia

Mini-uav remote control: a case study at Politecnico di Torino

Recent development of modern micro and nano technologies allows aerospace vehicles extremely small size to be constructed. Wide availability and mass production of small dimension components drastically reduce the price of such vehicles. This fact allows them to be constructed by Universities and it makes them useful for education. The Aerospace Systems Engineering Research Group (ASSET) at Politecnico di Torino the design, development and testing small, but quite complex, integrated systems. The goal of this paper is to present one of the contemporary works of this group: the Mini-UAV "ASSET" remote control/flight simulator site. This paper contains a short presentation of the Mini-UAV, a description of its onboard and ground systems and the use of COTS components. The paper explains how the ground control site has also been designed to run as a flight simulator. For this purpose MICROSOFT FLIGHT SIMULATOR for 3D scenario visualization and Matlab/Simulink for airplane and environmental modeling has been used and integrated. In the system are included possibilities of ALTIA Design software exploitation for avionic display visualization. In particular some new modes for HUD, conceived and simulated, are presented and discussed in the paper. The hardware configuration of the Remote Control System/Flight Simulator is briefly described

CO2 capture from natural gas combined cycles by CO2 selective membranes

This paper performs a techno-economic analysis of natural gas-fired combined cycle (NGCC) power plants integrated with CO2 selective membranes for post-combustion CO2 capture. The configuration assessed is based on a two-membrane system: a CO2 capture membrane that separates the CO2 for final sequestration and a CO2 recycle membrane that selectively recycles CO2 to the gas turbine compressor inlet in order to increase the CO2 concentration in the gas turbine flue gas. Three different membrane technologies with different permeability and selectivity have been investigated. The mass and energy balances are calculated by integrating a power plant model, a membrane model and a CO2 purification unit model. An economic model is then used to estimate the cost of electricity and of CO2 avoided. A sensitivity analysis on the main process parameters and economic assumptions is also performed. It was found that a combination of a high permeability membrane with moderate selectivity as a recycle membrane and a very high selectivity membrane with high permeability used for the capture membrane resulted in the lowest CO2 avoided cost of 75 US$/tCO2. This plant features a feed pressure of 1.5 bar and a permeate pressure of 0.2 bar for the capture membrane. This result suggests that membrane systems can be competitive for CO2 capture from NGCC power plants when compared with MEA absorption. However, to achieve significant advantages with respect to benchmark MEA capture, better membrane permeability and lower costs are needed with respect to the state of the art technology. In addition, due to the selective recycle, the gas turbine operates with a working fluid highly enriched with CO2. This requires redesigning gas turbine components, which may represent a major challenge for commercial deployment

Work-Related Mental Health and Job Performance: Can Mindfulness Help?

Work-related mental health issues such as work-related stress and addiction to work impose a significant health and economic burden to the employee, the employing organization, and the country of work more generally. Interventions that can be empirically shown to improve levels of work-related mental health – especially those with the potential to concurrently improve employee levels of work performance – are of particular interest to occupational stakeholders. One such broad-application interventional approach currently of interest to occupational stakeholders in this respect is mindfulness-based interventions (MBIs). Following a brief explication of the mindfulness construct, this paper critically discusses current research directions in the utilization of mindfulness in workplace settings and assesses its suitability for operationalization as an organization-level work-related mental health intervention. By effecting a perceptual-shift in the mode of responding and relating to sensory and cognitive-affective stimuli, employees that undergo mindfulness training may be able to transfer the locus of control for stress from external work conditions to internal metacognitive and attentional resources. Therefore, MBIs may constitute cost-effective organization-level interventions due to not actually requiring any modifications to human resource management systems and practises. Based on preliminary empirical findings and on the outcomes of MBI studies with clinical populations, it is concluded that MBIs appear to be viable interventional options for organizations wishing to improve the mental health of their employees

Artrópodes predadores em soja transgênica submetida a diferentes manejos fitossanitários.

Pouco se conhece sobre os efeitos de culturas geneticamente modificadas (GM) em insetos não-alvo, na sucessão soja-milho. O trabalho teve por objetivo avaliar a densidade de artrópodes predadores ocorrentes em soja transgênica, na sucessão soja-milho-soja, em diferentes sistemas de manejo fitossanitário. Foi utilizado o delineamento em blocos ao acaso com quatro repetições, compostas por parcelas de 18x18m. Os tratamentos consistiram de diferentes combinações de plantas transgênicas, na sucessão soja-milho: (T1) soja não-GM e milho não-Bt; (T2) soja não-GM e milhoBt; (T3) sojaRR e milho não-Bt; (T4) sojaRR e milhoBt; (T5) sojaBtRR e milho não-Bt; (T6) sojaBtRR e milho Bt; (T7) sojaRR e milhoBt com aplicação de inseticidas junto com herbicida e fungicida, totalizando 5 aplicações em soja e 3 em milho. De T1 a T6 os inseticidas foram aplicados de acordo com o nível de controle. As avaliações foram realizadas ao longo do segundo cultivo de soja da sucessão soja-milhosoja. Os predadores foram amostrados com rede entomológica, com 10 redadas nas linhas, em cada parcela. Os predadores com maior abundância foram submetidos à ANOVA e comparados por Tukey, quando os dados não atingiram os pressupostos foram submetidos a Kruskal-Wallis. Foram contabilizados 527 indivíduos, distribuídos em 14 táxons, além de 266 exemplares de Araneae, não identificadas. O táxon mais frequente foi Dolichopodidae, com 39,1% do total, seguido por Araneae (33,5%). Geocoris sp. (8,3%), Odontocheila nodicornis (6,2%), Orius sp. e Lebia concinna ocorreram em maior abundância, sendo comumente registradas como relevantes no controle biológico. Houve diferença estatística entre os tratamentos apenas para Araneae, sendo que as densidades nos tratamentos com soja Bt (T5 e T6) foi inferior aos outros com soja RR e não-GM. Provavelmente isso se deve ao fato de ocorrer menos lagartas em soja Bt, reduzindo a densidade populacional desse predador

A functional-cognitive framework for attitude research

In attitude research, behaviours are often used as proxies for attitudes and attitudinal processes. This practice is problematic because it conflates the behaviours that need to be explained (explanandum) with the mental constructs that are used to explain these behaviours (explanans). In the current chapter we propose a meta-theoretical framework that resolves this problem by distinguishing between two levels of analysis. According to the proposed framework, attitude research can be conceptualised as the scientific study of evaluation. Evaluation is defined not in terms of mental constructs but in terms of elements in the environment, more specifically, as the effect of stimuli on evaluative responses. From this perspective, attitude research provides answers to two questions: (1) Which elements in the environment moderate evaluation? (2) What mental processes and representations mediate evaluation? Research on the first question provides explanations of evaluative responses in terms of elements in the environment (functional level of analysis); research on the second question offers explanations of evaluation in terms of mental processes and representations (cognitive level of analysis). These two levels of analysis are mutually supportive, in that better explanations at one level lead to better explanations at the other level. However, their mutually supportive relation requires a clear distinction between the concepts of their explanans and explanandum, which are conflated if behaviours are treated as proxies for mental constructs. The value of this functional-cognitive framework is illustrated by applying it to four central questions of attitude research

Mindfulness-based interventions for people diagnosed with a current episode of an anxiety or depressive disorder: a meta-analysis of randomised controlled trials

Objective Mindfulness-based interventions (MBIs) can reduce risk of depressive relapse for people with a history of recurrent depression who are currently well. However, the cognitive, affective and motivational features of depression and anxiety might render MBIs ineffective for people experiencing current symptoms. This paper presents a meta-analysis of randomised controlled trials (RCTs) of MBIs where participants met diagnostic criteria for a current episode of an anxiety or depressive disorder. Method Post-intervention between-group Hedges g effect sizes were calculated using a random effects model. Moderator analyses of primary diagnosis, intervention type and control condition were conducted and publication bias was assessed. Results Twelve studies met inclusion criteria (n = 578). There were significant post-intervention between-group benefits of MBIs relative to control conditions on primary symptom severity (Hedges g = −0.59, 95% CI = −0.12 to −1.06). Effects were demonstrated for depressive symptom severity (Hedges g = −0.73, 95% CI = −0.09 to −1.36), but not for anxiety symptom severity (Hedges g = −0.55, 95% CI = 0.09 to −1.18), for RCTs with an inactive control (Hedges g = −1.03, 95% CI = −0.40 to −1.66), but not where there was an active control (Hedges g = 0.03, 95% CI = 0.54 to −0.48) and effects were found for MBCT (Hedges g = −0.39, 95% CI = −0.15 to −0.63) but not for MBSR (Hedges g = −0.75, 95% CI = 0.31 to −1.81). Conclusions This is the first meta-analysis of RCTs of MBIs where all studies included only participants who were diagnosed with a current episode of a depressive or anxiety disorder. Effects of MBIs on primary symptom severity were found for people with a current depressive disorder and it is recommended that MBIs might be considered as an intervention for this population