Complex Networks from Classical to Quantum

Recent progress in applying complex network theory to problems in quantum information has resulted in a beneficial crossover. Complex network methods have successfully been applied to transport and entanglement models while information physics is setting the stage for a theory of complex systems with quantum information-inspired methods. Novel quantum induced effects have been predicted in random graphs---where edges represent entangled links---and quantum computer algorithms have been proposed to offer enhancement for several network problems. Here we review the results at the cutting edge, pinpointing the similarities and the differences found at the intersection of these two fields.Comment: 12 pages, 4 figures, REVTeX 4-1, accepted versio

Remote data acquisition for condition monitoring of wind turbines

While the number of offshore wind turbines is growing and turbines getting bigger and more expensive, the need for good condition monitoring systems is rising. From the research it is clear that failures of the gearbox, and in particular the gearwheels and bearings of the gearbox, have been responsible for the most downtime of a wind turbine. Gearwheels and bearings are being simulated in a multi-sensor environment to observe the wear on the surface

Tribological behaviour of polymer bearings under dry and water lubrication

This study attempts to evaluate the performance of polymer journal bearings (PET and UHMWPE) sliding against Inconel stainless steel in both dry and lubricated condition. Four types of ‘lubricant’ are included: distilled water; demineralized water; tap water and river water. The tests were carried out in a so called “Stribeck” configuration with a projected pressure of about 0.3 MPa at room temperature and sliding speed ranging from 0 to 1.07 m/s respectively. The study indicates that polymer bearings with four types of water lubricant give better tribological behaviour compared to those in dry sliding contact. Besides, with water lubrication, UHMWPE shows low friction at starting, but it does not go down much over the course of the tests. Meanwhile, although PET indicates quite higher friction at the beginning, it then shows a clearly decreasing trend

Banking risk and regulation: Does one size fit all?

Using data for more than 200 banks from 21 OECD countries for the period 2002 to 2008, we examine the impact of bank regulation and supervision on banking risk. Supervisory control, and regulations on capital and market entry have a significant impact on 'capital and asset risk', while supervisory control and regulations on activities restrictions, private monitoring, market entry, and liquidity, have a significant effect on 'liquidity and market risk'. However, quantile regressions suggest that the effect of regulation and supervision differs across banks: most indicators of bank regulation and supervision do not have a significant effect on low-risk banks, while they do affect high-risk banks.

Pension fund sophistication and investment policy

This paper assesses the sophistication of pension funds' investment policies using data on 748 Dutch pension funds during the 1999.2006 period. We develop three indicators of sophistication: gross rounding of investment choices, investments in alternative sophisticated asset classes and 'home bias'. We find that pension funds' strategic portfolio choices are often based on coarse and possibly less sophisticated approaches. Most pension funds, particularly the medium-sized and smaller ones, round strategic asset allocations to the nearest multiple of 5%, similar to age heaping in demographic and historical studies. Second, many pension funds invest little or nothing in alternative asset classes besides equities and bonds, resulting in limited asset diversification. Third, medium-sized and smaller pension funds favor regional investments and as such not fully employ the opportunities of international diversification. Finally, we show that pension funds using less sophisticated asset allocation rules tend to opt for investment strategies with a lower risk-return profile.Pension funds, investment policy, portfolio choice, gross rounding, heaping, diversification, home bias, alternative investments, behavioral finance.

Fragmented government effects on fiscal policy: new evidence

Most industrialized countries entered the 1980s with their public finances in disarray. At the time, persistent deficits pushed up public debt-to-GDP ratios. Despite such similarities, deficit spending varies substantially between countries and within countries over time. Recent theoretical and empirical research has considered how differences in political arrangements affecting national policy formation might explain variation in fiscal policies pursued. Using a panel of 22 OECD countries over the 1971-1996 period this paper extends previous literature on the effects of fragmented government on fiscal policy outcomes in various directions. First, we focus on data relating to central government instead of general government as all theories refer to central government. Second, not only do we analyze the effect of size fragmentation of government, we also examine government's position vis-à-vis parliament and government's political fragmentation. We find evidence that more fragmented government (defined in terms of the number of political parties in a coalition or the number of spending ministers) have higher deficits. There is also some evidence that governments that dispose of excess seats in parliament have lower deficits. Right-wing governments appear to have been fiscally more responsible in the seventies. Political fragmentation does not affect government's budget deficit.

Manipulating matter waves in an optical superlattice

We investigate the potential for controlling a non-interacting Bose-Einstein condensate loaded into a one-dimensional optical superlattice. Our control strategy combines Bloch oscillations originating from accelerating the lattice and from time-dependent control of the superlattice parameters. We investigate two experimentally viable scenarios, very low and very high potential depths. We are able to exhibit a wide range of control over energy band populations using the superlattice control parameters. With this analysis we consider several examples of quantum state preparation in the superlattice structure that may be difficult to achieve in a regular lattice.Comment: 9 pages, 11 figures. Updated version as an artist's work is never finished, and due to publication. DOI & journal ref adde