The Science of Monetary Policy: A New Keynesian Perspective

MONETARY POLICY; STABILIZATION; CREDIBILITY.

Polarization mode dispersion in radio-frequency interferometric embedded fiber-optic sensors

The effect of fiber birefringence on the propagation delay in an embedded fiber-optic strain sensor is studied. The polarization characteristics of the sensor are described in terms of polarization mode dispersion through the principal states of polarization and their differential group delay. Using these descriptors, an analytical expression for the response of the sensor for an arbitrary input state of polarization is given and experimentally verified. It is found that the differential group delay, as well as the input and output principal states of polarization, vary when the embedded fiber is strained, leading to fluctuations in the sensor output. The use of high birefringence fibers and different embedding geometries is examined as a means for reducing the polarization dependency of the sensor

Dark states of single NV centers in diamond unraveled by single shot NMR

The nitrogen-vacancy (NV) center in diamond is supposed to be a building block for quantum computing and nanometer scale metrology at ambient conditions. Therefore, precise knowledge of its quantum states is crucial. Here, we experimentally show that under usual operating conditions the NV exists in an equilibrium of two charge states (70% in the expected negative (NV-) and 30% in the neutral one (NV0)). Projective quantum non-demolition measurement of the nitrogen nuclear spin enables the detection even of the additional, optically inactive state. The nuclear spin can be coherently driven also in NV0 (T1 ~ 90 ms and T2 ~ 6 micro-s).Comment: 4 pages, 3 figure

Numerical study of SQUID array responses due to asymmetric junction parameters

Superconducting quantum interference device arrays have been extensively studied for their high magnetic field sensitivity. The performance of these devices strongly depends on the characteristic parameters of their Josephson junctions, i.e. their critical currents and shunt resistances. Using a resistively shunted junction model and including thermal noise, we perform a numerical investigation of the effects of asymmetric Josephson junctions by independently studying variations in the critical currents and junction resistances. We compare the voltage response of a dc-SQUID with a 1D parallel SQUID array and study the maximum transfer function dependence on the number of junctions in parallel, the screening parameter and thermal noise strength. Our results show that the maximum transfer function and linearity increase with the number of junctions in parallel for arrays with different junction resistances, in contrast to SQUID arrays with identical junctions or with spreads in the critical currents

Entrepreneurial orientation and firm performance in the context of upper echelon theory.

Entrepreneurial Orientation (EO) is a firm-level phenomenon, which involves the firm’s prospects to take risks, be proactive, and be innovative. Most of the research assumes a positive EO-performance relationship adopting the EO-as-advantage perspective without providing enough theoretical foundations of the way EO enhances performance. This paper provides insights into the EO and firm performance relationship looking into the EO-as-experimentation perspective. Through EO-as-experimentation perspective, we argue for the importance of looking into the differential effects of each of the EO dimensions on firm performance in active and inactive firms. We hypothesized that the effect of each of the proactiveness and innovativeness dimension of EO on firm performance is positive among active firms and negative among inactive firms. Whereas risk taking dimension of EO is negative among active and inactive firms. Based on the results of firm fixed effect regression some empirical support for the hypotheses is presented and discussed

Carbon antisite clusters in SiC: a possible pathway to the D_{II} center

The photoluminescence center D_{II} is a persistent intrinsic defect which is common in all SiC polytypes. Its fingerprints are the characteristic phonon replicas in luminescence spectra. We perform ab-initio calculations of vibrational spectra for various defect complexes and find that carbon antisite clusters exhibit vibrational modes in the frequency range of the D_{II} spectrum. The clusters possess very high binding energies which guarantee their thermal stability--a known feature of the D_{II} center. The di-carbon antisite (C_{2})_{Si} (two carbon atoms sharing a silicon site) is an important building block of these clusters.Comment: RevTeX 4, 6 pages, 3 figures Changes in version 2: Section headings, footnote included in text, vibrational data now given for neutral split-interstitial, extended discussion of the [(C_2)_Si]_2 defect incl. figure Changes version 3: Correction of binding energy for 3rd and 4th carbon atom at antisite; correction of typo

Monetary Policy Rules and Macroeconomic Stability: Evidence and some Theory

We estimate a forward-looking monetary policy reaction function for the postwar U.S. economy, pre- and post-October 1979. Our results point to substantial differences in the estimated rule across periods. In particular, interest rate policy in the Volcker-Greenspan period appears to have been much mors sensitive to changes in expected inflation than in the pre-Volcker period.BUSINESS CYCLES ; MONETARY POLICY