1,850 research outputs found
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Inflation Co-movement across Countries in Multi-maturity Term Structure: An Arbitrage-Free Approach
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Estimation of NAIRU with In ation Expectation Data
Estimating natural rate of unemployment (NAIRU) is important for understanding the joint dynamics of unemployment, inflation, and inflation expectation. However, existing literature falls short of endogenizing inflation expectation together with NAIRU in a model consistent way. We estimate a structural model with forward and backward looking Phillips curve. Inflation expectation is treated as a function of state variables and we use survey data as its noisy observations. Surprisingly, we find that the estimated NAIRU tracks unemployment rate closely, except for the high inflation period (late 1970s). Compared to the estimation without using the survey data, the estimated Bayesian credible sets are narrower and our model leads to better inflation and unemployment forecasts. These results suggest that monetary policy was very effective and there was not much room for policy improvement
Quantum Entanglement in Heisenberg Antiferromagnets
Entanglement sharing among pairs of spins in Heisenberg antiferromagnets is
investigated using the concurrence measure. For a nondegenerate S=0 ground
state, a simple formula relates the concurrence to the diagonal correlation
function. The concurrence length is seen to be extremely short. A few finite
clusters are studied numerically, to see the trend in higher dimensions. It is
argued that nearest-neighbour concurrence is zero for triangular and Kagome
lattices. The concurrences in the maximal-spin states are explicitly
calculated, where the concurrence averaged over all pairs is larger than the
S=0 states.Comment: 7 pages, 3 figure
Quantum State Reconstruction of Many Body System Based on Complete Set of Quantum Correlations Reduced by Symmetry
We propose and study a universal approach for the reconstruction of quantum
states of many body systems from symmetry analysis. The concept of minimal
complete set of quantum correlation functions (MCSQCF) is introduced to
describe the state reconstruction. As an experimentally feasible physical
object, the MCSQCF is mathematically defined through the minimal complete
subspace of observables determined by the symmetry of quantum states under
consideration. An example with broken symmetry is analyzed in detail to
illustrate the idea.Comment: 10 pages, n figures, Revte
Maximal Entanglement of Two-qubit States Constructed by Linearly Independent Coherent States
In this paper, we find the necessary and sufficient condition for the maximal
entanglement of the state, constructed by linearly independent
coherent states with \emph{real parameters} when
. This is a further generalization of the
classified nonorthogonal states discussed in Ref. Physics Letters A {\bf{291}},
73-76 (2001).Comment: some examples added; Int J Theor Phys 201
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LASSO-Driven Inference in Time and Space
We consider the estimation and inference in a system of high-dimensional regression equations allowing for temporal and cross-sectional dependency in covariates and error processes, covering rather general forms of weak dependence. A sequence of large-scale regressions with LASSO is applied to reduce the dimensionality, and an overall penalty level is carefully chosen by a block multiplier bootstrap procedure to account for multiplicity of the equations and dependencies in the data. Correspondingly, oracle properties with a jointly selected tuning parameter are derived. We further provide high-quality de-biased simultaneous inference on the many target parameters of the system. We provide bootstrap consistency results of the test procedure, which are based on a general Bahadur representation for the Z-estimators with dependent data. Simulations demonstrate good performance of the proposed inference procedure. Finally, we apply the method to quantify spillover effects of textual sentiment indices in a financial market and to test the connectedness among sectors
Social work education as a catalyst for social change and social development: case study of a Master of Social Work Program in China
In response to the urgent need for professionally trained social workers to help in alleviating emerging social problems in China after the introduction of the market economy, the Hong Kong Polytechnic University and the Peking University launched a Master of Social Work (China) Program for social work educators in 2000, with the aim of developing a critical mass of social work educators to take up the future leadership in developing social work and social work education in China. To date, seven cohorts of over 230 students consisting of social work educators, NGO and government officials have been admitted to the program, and graduates of the program are playing a pivotal role in spearheading the development of social work education and fostering social development through the process. In this paper, the authors will present the vision and mission of the Master of Social Work (MSW) Program, the teaching and learning strategies adopted, and the ways in which the program has facilitated social change and social development through its educational process
Mechanism of Enhancement in Electromagnetic Properties of MgB2 by Nano SiC Doping
A comparative study of pure, SiC, and C doped MgB2 wires has revealed that the SiC doping allowed C substitution and MgB2 formation to take place simultaneously at low temperatures. C substitution enhances Hc2, while the defects, small grain size, and nanoinclusions induced by C incorporation and low-temperature processing are responsible for the improvement in Jc. The irreversibility field (Hirr) for the SiC doped sample reached the benchmarking value of 10 T at 20 K, exceeding that of NbTi at 4.2 K. This dual reaction model also enables us to predict desirable dopants for enhancing the performance properties of MgB2
Thermal and ground-state entanglement in Heisenberg XX qubit rings
We study the entanglement of thermal and ground states in Heisernberg
qubit rings with a magnetic field. A general result is found that for
even-number rings pairwise entanglement between nearest-neighbor qubits is
independent on both the sign of exchange interaction constants and the sign of
magnetic fields. As an example we study the entanglement in the four-qubit
model and find that the ground state of this model without magnetic fields is
shown to be a four-body maximally entangled state measured by the -tangle.Comment: Four pages and one figure, small change
Molecular Beam Epitaxy of Ga(In)AsN/GaAs Quantum Wells towards 1.3µm and 1.55µm
In this article, we report an attempt of extending the InGaAsN materials towards 1.3µm and 1.55µm wavelength. All these InGaAsN samples are grown in a plasma-assisted solid-source molecular-beam epitaxy (SS-MBE) system. Our experiments revealed that the nitrides could be grown with both direct nitrogen beam and dispersive nitrogen. The nitrogen incorporation rate could be reduced by the presence of indium flux. The interaction between nitrogen and indium might lead to 3D growth mode and growth dynamics. It is proved that the increasing growth rate reduces the nitrogen incorporation efficiency. The data for nitrogen sticking coefficient are somewhat contradictive. The growth with dispersive nitrogen source causes the improvement of material quality. Fixed indium flux is a better way for the wavelength control. Also, we report some growth optimization work for better PL property and the annealing effect on the samples. Literature is sometimes reviewed for comparison.Singapore-MIT Alliance (SMA
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