Managing financial risks in Papua New Guinea : an optimal external debt portfolio

This report shows that Papua New Guinea's assets and liabilities may be poorly balanced for debt servicing. Thus, it could benefit substantially from active risk management, especially through better selection of the financial instruments in its debt portfolio. The authors present a model and estimate of an optiomal debt portfolio that allows for the use of commodity-linked bonds and conventional debt denominated in different currencies. They judge the hedging effectiveness of this portfolio by how much the variance of expected real import is reduced. The results indicate that commodity-linked bonds could play an important role in the country's risk management strategy. They also show that the country's external debt structure is not well balanced to hedge the foreign exchange risk from the existing composition of non-U.S. dollar-denominated liabilities. The debt portfolio contains an excess of Japanese yen - and Deutschemark - denominated liabilities, while liabilities denominated in British pounds are substantially underrepresented.Economic Theory&Research,Environmental Economics&Policies,Public Sector Economics&Finance,Settlement of Investment Disputes,Strategic Debt Management

A SIMULTANEOUS EQUATION MODEL OF THE ECONOMIC-ECOLOGIC SYSTEM IN CITRUS GROVES

Crop Production/Industries,

Chiral anomaly of Weyl magnons in stacked honeycomb ferromagnets

Chiral anomaly of Weyl magnons (WMs), featured by nontrivial band crossings at paired Weyl nodes (WNs) of opposite chirality, is investigated. It is shown that WMs can be realized in stacked honeycomb ferromagnets. Using the Aharonov-Casher effect that is about the interaction between magnetic moments and electric fields, the magnon motion in honeycomb layers can be quantized into magnonic Landau levels (MLLs). The zeroth MLL is chiral so that unidirectional WMs propagate in the perpendicular (to the layer) direction for a given WN under a magnetic field gradient from one WN to the other and change their chiralities, resulting in the magnonic chiral anomaly (MCA). A net magnon current carrying spin and heat through the zeroth MLL depends linearly on the magnetic field gradient and the electric field gradient in the ballistic transport.Comment: 8 pages, 8 figure

Optimal universal programmable detectors for unambiguous discrimination

We discuss the problem of designing unambiguous programmable discriminators for any n unknown quantum states in an m-dimensional Hilbert space. The discriminator is a fixed measurement that has two kinds of input registers: the program registers and the data register. The quantum state in the data register is what users want to identify, which is confirmed to be among the n states in program registers. The task of the discriminator is to tell the users which state stored in the program registers is equivalent to that in the data register. First, we give a necessary and sufficient condition for judging an unambiguous programmable discriminator. Then, if $m=n$, we present an optimal unambiguous programmable discriminator for them, in the sense of maximizing the worst-case probability of success. Finally, we propose a universal unambiguous programmable discriminator for arbitrary n quantum states.Comment: 7 page