4,034 research outputs found
Identifying the influences of nominal and real rigidities in aggregate price-setting behavior
We formulate a generalized price-setting framework that incorporates staggered contracts of multiple durations and that enables us to directly identify the influences of nominal vs. real rigidities. Using German macroeconomic data over the period 1975Q1 through 1998Q4 toestimate this framework, we find that the data is well-characterized by a truncated Calvostyle distribution with an average duration of about two quarters. We also find that new contracts exhibit very low sensitivity to marginal cost, corresponding to a relatively high degree of real rigidity. Finally, our results indicate that backward-looking behavior is not needed to explain the aggregate data, at least in an environment with a stable monetary policy regime and a transparent and credible inflation objective. JEL Classification: E31, E52Inflation persistence, nominal rigidity, overlapping contracts, real rigidity, simulation-based indirect inference
Data uncertainty and the role of money as an information variable for monetary policy
This paper shows that money can play an important role as an information variable when initial output data are measured with error and subject to revision. Using an estimated model of the euro area we find that current output estimates may be substantially improved by including money growth in the information set. The gain in precision, however, depends on the magnitude of the output measurement error relative to the money demand shock. We find noticable but small improvements in output estimates, if the uncertainty due to money demand shocks corresponds to the estimated variance obtained from the money demand equation. Money plays a quantitatively more important role with regard to output estimation if we allow for a contribution of monetary analysis in reducing uncertainty due to money demand shocks. In this case, money also helps to reduce uncertainty about output forecasts JEL Classification: E31, E52, E58, E61euro area, Kalman ?lter, macroeconomic modelling, measurement error, monetary policy rules, Rational Expectations
Exceptional Points in Atomic Spectra
We report the existence of exceptional points for the hydrogen atom in
crossed magnetic and electric fields in numerical calculations. The resonances
of the system are investigated and it is shown how exceptional points can be
found by exploiting characteristic properties of the degeneracies, which are
branch point singularities. A possibility for the observation of exceptional
points in an experiment with atoms is proposed.Comment: 4 pages, 4 figures, 1 table, to be published in Physical Review
Letter
Confinement induced molecules in a 1D Fermi gas
We have observed two-particle bound states of atoms confined in a
one-dimensional matter wave guide. These bound states exist irrespective of the
sign of the scattering length, contrary to the situation in free space. Using
radio-frequency spectroscopy we have measured the binding energy of these
dimers as a function of the scattering length and confinement and find good
agreement with theory. The strongly interacting one-dimensional Fermi gas which
we create in an optical lattice represents a realization of a tunable Luttinger
liquid.Comment: 4 page
Lorentz Violation for Photons and Ultra-High Energy Cosmic Rays
Lorentz symmetry breaking at very high energies may lead to photon dispersion
relations of the form omega^2=k^2+xi_n k^2(k/M_Pl)^n with new terms suppressed
by a power n of the Planck mass M_Pl. We show that first and second order terms
of size xi_1 > 10^(-14) and xi_2 < -10^(-6), respectively, would lead to a
photon component in cosmic rays above 10^(19) eV that should already have been
detected, if corresponding terms for electrons and positrons are significantly
smaller. This suggests that Lorentz invariance breakings suppressed up to
second order in the Planck scale are unlikely to be phenomenologically viable
for photons.Comment: 4 revtex pages, 3 postscript figures included, version published in
PR
Quantum network architecture of tight-binding models with substitution sequences
We study a two-spin quantum Turing architecture, in which discrete local
rotations \alpha_m of the Turing head spin alternate with quantum controlled
NOT-operations. Substitution sequences are known to underlie aperiodic
structures. We show that parameter inputs \alpha_m described by such sequences
can lead here to a quantum dynamics, intermediate between the regular and the
chaotic variant. Exponential parameter sensitivity characterizing chaotic
quantum Turing machines turns out to be an adequate criterion for induced
quantum chaos in a quantum network.Comment: Accepted for publication in J. mod. Optics [Proc. Workshop
"Entanglement and Decoherence", Gargnano (Italy), Sept 1999], 3 figure
Ultra-High Energy Cosmic Rays and the GeV-TeV Diffuse Gamma-Ray Flux
Ultra-high energy cosmic ray protons accelerated in astrophysical objects
produce secondary electromagnetic cascades during propagation in the cosmic
microwave and infrared backgrounds. We show that such cascades can contribute
between ~1% and ~50% of the GeV-TeV diffuse photon flux measured by the EGRET
experiment. The GLAST satellite should have a good chance to discover this
flux.Comment: 4 pages, 5 figure
Identifying the influences of nominal and real rigidities in aggregate price-setting behavior
We formulate a generalized price-setting framework that incorporates staggered contracts of multiple durations and that enables us to directly identify the influences of nominal vs. real rigidities. Using German macroeconomic data over the period 1975Q1 through 1998Q4 toestimate this framework, we find that the data is well-characterized by a truncated Calvostyle distribution with an average duration of about two quarters. We also find that new contracts exhibit very low sensitivity to marginal cost, corresponding to a relatively high degree of real rigidity. Finally, our results indicate that backward-looking behavior is not needed to explain the aggregate data, at least in an environment with a stable monetary policy regime and a transparent and credible inflation objective
Cavity-induced temperature control of a two-level system
We consider a two-level atom interacting with a single mode of the
electromagnetic field in a cavity within the Jaynes-Cummings model. Initially,
the atom is thermal while the cavity is in a coherent state. The atom interacts
with the cavity field for a fixed time. After removing the atom from the cavity
and applying a laser pulse the atom will be in a thermal state again. Depending
on the interaction time with the cavity field the final temperature can be
varied over a large range. We discuss how this method can be used to cool the
internal degrees of freedom of atoms and create heat baths suitable for
studying thermodynamics at the nanoscale
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