11,645 research outputs found
Multivariate Markov switching with weighted regime determination: giving France more weight than Finland
This article deals with using panel data to infer regime changes that are common to all of the cross section. The methods presented here apply to Markov switching vector autoregressions, dynamic factor models with Markov switching and other multivariate Markov switching models. The key feature we seek to add to these models is to permit cross-sectional units to have different weights in the calculation of regime probabilities. We apply our approach to estimating a business cycle chronology for the 50 U.S. States and the Euro area, and we compare results between country-specific weights and the usual case of equal weights. The model with weighted regime determination suggests that Europe experienced a recession in 2002-03, whereas the usual model with equal weights does not.Business cycles ; France ; Finland
Ground-state energy and stability limit of small 3He drops
Small and stable drops of 3He atoms can only exist above a minimum number of
particles, due to the combination of the 3He atom Fermi statistics and its
light mass. An accurate estimation of this minimum number using microscopic
theory has been difficult due to the inhomogeneous and fermionic nature of
these systems. We present a diffusion Monte Carlo calculation of 3He drops with
sizes near the minimum in order to determine the stability threshold. The
results show that the minimum self-bound drop is formed by N=30 atoms with
preferred orbitals for open shells corresponding to maximum value of the spin.Comment: 5 pages, 4 figure
Self-calibrating d-scan: measuring ultrashort laser pulses on-target using an arbitrary pulse compressor
In most applications of ultrashort pulse lasers, temporal compressors are
used to achieve a desired pulse duration in a target or sample, and precise
temporal characterization is important. The dispersion-scan (d-scan) pulse
characterization technique usually involves using glass wedges to impart
variable, well-defined amounts of dispersion to the pulses, while measuring the
spectrum of a nonlinear signal produced by those pulses. This works very well
for broadband few-cycle pulses, but longer, narrower bandwidth pulses are much
more difficult to measure this way. Here we demonstrate the concept of
self-calibrating d-scan, which extends the applicability of the d-scan
technique to pulses of arbitrary duration, enabling their complete measurement
without prior knowledge of the introduced dispersion. In particular, we show
that the pulse compressors already employed in chirped pulse amplification
(CPA) systems can be used to simultaneously compress and measure the temporal
profile of the output pulses on-target in a simple way, without the need of
additional diagnostics or calibrations, while at the same time calibrating the
often-unknown differential dispersion of the compressor itself. We demonstrate
the technique through simulations and experiments under known conditions.
Finally, we apply it to the measurement and compression of 27.5 fs pulses from
a CPA laser.Comment: 11 pages, 5 figures, Scientific Reports, in pres
Top-Quark Production and Decay in the MSSM
We review the features of top-quark decays and loop-induced effects in the
production cross section and CP-violating observables of e+e- -> t t-bar which
are specific to the R-parity conserving Minimal Supersymmetric Standard Model
(MSSM).Comment: LaTeX, 28 pages, 10 figures included, uses cite.sty. Contribution to
the proceedings of the 2nd Joint ECFA/DESY Workshop on Physics and Detectors
for a Linear Electron-Positron Collider. References adde
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