The dynamical Casimir effect in superconducting microwave circuits

We theoretically investigate the dynamical Casimir effect in electrical circuits based on superconducting microfabricated waveguides with tunable boundary conditions. We propose to implement a rapid modulation of the boundary conditions by tuning the applied magnetic flux through superconducting quantum interference devices (SQUIDs) that are embedded in the waveguide circuits. We consider two circuits: (i) An open waveguide circuit that corresponds to a single mirror in free space, and (ii) a resonator coupled to a microfabricated waveguide, which corresponds to a single-sided cavity in free space. We analyze the properties of the dynamical Casimir effect in these two setups by calculating the generated photon-flux density, output-field correlation functions, and the quadrature squeezing spectra. We show that these properties of the output field exhibit signatures unique to the radiation due to the dynamical Casimir effect, and could therefore be used for distinguishing the dynamical Casimir effect from other types of radiation in these circuits. We also discuss the similarities and differences between the dynamical Casimir effect, in the resonator setup, and downconversion of pump photons in parametric oscillators.Comment: 18 pages, 14 figure

Stock and Bond Relationships in Asia

This paper analyzes the relationship between stocks and bonds in nine Asian countries. Using a bivariate stochastic volatility model, we show that there are significant volatility spillover effects between stock and bond markets in several of the countries. Furthermore, dynamic correlation patterns show that the relationship between stock and bond markets changes considerably over time in all countries. Stock-bond correlation increases during periods of turmoil in several countries, indicating that there is a cross-asset contagion effect. Therefore, if there is a flight to quality effect in Asian markets, it seems to occur across countries or regions rather than across domestic assets. The results have direct and important implications for regional policy makers as well as domestic and international investors that invest in multiple asset classes.Asia; stock markets; bond markets; stochastic volatility; Markov Chain Monte Carlo; spillover effects; dynamic correlation

Asian Sovereign Debt and Country Risk

This paper analyzes systematic risk of sovereign bonds in four East Asian countries: China, Malaysia, Philippines, and Thailand. A bivariate stochastic volatility model that allows for time-varying correlation is estimated with Markov Chain Monte Carlo simulation. The volatilities and correlation are then used to calculate the time-varying betas. The results show that country-specific systematic risk in Asian sovereign bonds varies over time. When adjusting for inherent exchange rate risk, the pattern of systematic risk is similar, even though the level is generally lower. The findings have important implications for international portfolio managers that invest in emerging sovereign bonds and those who need benchmark instruments to analyze risk in assets such as corporate bonds in the emerging Asian financial markets.Asia; sovereign bonds; systematic risk; stochastic volatility; Markov Chain Monte Carlo

Participant Bidding Enhances Cost Effectiveness

A multitude of design decisions influence the performance of voluntary conservation programs. This Economic Brief is one of a set of five exploring the implications of decisions policymakers and program managers must make about who is eligible to receive payments, how much can be received, for what action, and the means by which applicants are selected. The particular issue examined here is the potential benefits of allowing farmers to "bid" for the activity they will undertake and the level of payment they would receive for it.Agricultural and Food Policy, Environmental Economics and Policy,

Watershed Nutrient Trading Under Asymmetric Information

This study evaluates first- and second-best trading policies for regulating watershed phosphorus under asymmetric information. The trading policies are differentiated on the degree to which regulators observe point and nonpoint source abatement efforts. The efficiency losses attributable to these informational asymmetries and those of the second-best policies can be measured in social welfare, and provide regulators the shadow value of foregoing first-best measures. Given representative monitoring costs from national water monitoring programs, it is shown that under asymmetric information, the chosen second-best trading policies outperform first-best policies by 11% in the control of watershed nutrient pollution.Environmental Economics and Policy,

Fast and accurate evaluation of Wigner 3j, 6j, and 9j symbols using prime factorisation and multi-word integer arithmetic

We present an efficient implementation for the evaluation of Wigner 3j, 6j, and 9j symbols. These represent numerical transformation coefficients that are used in the quantum theory of angular momentum. They can be expressed as sums and square roots of ratios of integers. The integers can be very large due to factorials. We avoid numerical precision loss due to cancellation through the use of multi-word integer arithmetic for exact accumulation of all sums. A fixed relative accuracy is maintained as the limited number of floating-point operations in the final step only incur rounding errors in the least significant bits. Time spent to evaluate large multi-word integers is in turn reduced by using explicit prime factorisation of the ingoing factorials, thereby improving execution speed. Comparison with existing routines shows the efficiency of our approach and we therefore provide a computer code based on this work.Comment: 7 pages, 2 figures. Accepted for publication in SIAM Journal on Scientific Computing (SISC

WHAT MOVES BOND YIELDS IN CHINA?

This paper analyzes the joint dynamic processes of macroeconomic and monetary variables and bond yields in China. We show that macroeconomic variables as well as monetary policy variables have a significant impact on two factors that capture the variation in yields. An increase in the inflation rate and economic growth result in a rise in the yield curve. Similarly, an increase in the money supply causes a rise in the yield curve, albeit with a delayed effect. Finally, when official rates are raised, the long yield shows signs of a delayed decline. Overall, the long yield is more sensitive to most changes in macroeconomic and monetary variables. These results differ from an earlier study on bond yields by Ang and Piazzesi (2003), who show that the U.S. short-term rate is more sensitive to changes in macroeconomic variables. Possible explanations for the difference include certain unique structural features in the domestic financial system and the way monetary policy is conducted in China.China; yield curve; macroeconomic factors; monetary policy