11,028 research outputs found
On growth of spinodal instabilities in nuclear matter-II:asymmetric matter
As an extension of our previous work, the growth of density fluctuations in
the spinodal region of charge asymmetric nuclear matter is investigated in the
basis of the stochastic mean-field approach in the non-relativistic framework.
A complete treatment of density correlation functions are presented by
including collective modes and non-collective modes as well.Comment: 20 pages, 6 figures, Accepted by Physical Review
Polarization Beam Splitter Based on Self-Collimation of a Hybrid Photonic Crystal
A photonic crystal polarization beam splitter based on photonic band gap and self-collimation effects is designed for optical communication wavelengths. The photonic crystal structure consists of a polarization-insensitive self-collimation region and a splitting region. TM- and TE-polarized waves propagate without diffraction in the self-collimation region, whereas they split by 90 degrees in the splitting region. Efficiency of more than 75% for TM- and TE-polarized light is obtained for a polarization beam splitter size of only 17 ÎĽm x 17 ÎĽm in a wavelength interval of 60 nm including 1.55 ÎĽm
Equality of averaged and quenched large deviations for random walks in random environments in dimensions four and higher
We consider large deviations for nearest-neighbor random walk in a uniformly
elliptic i.i.d. environment. It is easy to see that the quenched and the
averaged rate functions are not identically equal. When the dimension is at
least four and Sznitman's transience condition (T) is satisfied, we prove that
these rate functions are finite and equal on a closed set whose interior
contains every nonzero velocity at which the rate functions vanish.Comment: 17 pages. Minor revision. In particular, note the change in the title
of the paper. To appear in Probability Theory and Related Fields
Electron muon identification by atmospheric shower and electron beam in a new concept of an EAS detector
We present results demonstrating the time resolution and /e separation
capabilities with a new concept of an EAS detector capable for measurements of
cosmic rays arriving with large zenith angles. This kind of detector has been
designed to be a part of a large area (several square kilometers) surface array
designed to measure Ultra High Energy (10-200 PeV) neutrinos using the
Earth-skimming technique. A criteria to identify electron-gammas is also shown
and the particle identification capability is tested by measurements in
coincidence with the KASKADE-GRANDE experiment in Karlsruhe, Germany.Comment: accepted by Astrophysical Journal on January 12 2015, 16 pages 3
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A Cyclical Model of Exchange Rate Volatility
In this paper, we investigate the long run dynamics of the intraday range of the GBP/USD, JPY/USD and CHF/USD exchange rates. We use a non-parametric filter to extract the low frequency component of the intraday range, and model the cyclical deviation of the range from the long run trend as a stationary autoregressive process. We find that the long run trend is time-varying but highly persistent, while the cyclical component is strongly mean reverting. This has important implications for modelling and forecasting volatility over both short and long horizons. As an illustration, we use the cyclical volatility model to generate out-of-sample forecasts of exchange rate volatility for horizons of up to one year under the assumption that the long run trend is fully persistent. As a benchmark, we compare the forecasts of the cyclical volatility model with those of the two-factor intraday range-based EGARCH model of Brandt and Jones (2006). Not only is the cyclical volatility model significantly easier to estimate than the EGARCH model, but it also offers a substantial improvement in out-of-sample forecast performance.Conditional volatility, Intraday range, Hodrick-Prescott filter
Gravity on a parallelizable manifold. Exact solutions
The wave type field equation \square \vt^a=\la \vt^a, where \vt^a is a
coframe field on a space-time, was recently proposed to describe the gravity
field. This equation has a unique static, spherical-symmetric,
asymptotically-flat solution, which leads to the viable Yilmaz-Rosen metric. We
show that the wave type field equation is satisfied by the pseudo-conformal
frame if the conformal factor is determined by a scalar 3D-harmonic function.
This function can be related to the Newtonian potential of classical gravity.
So we obtain a direct relation between the non-relativistic gravity and the
relativistic model: every classical exact solution leads to a solution of the
field equation. With this result we obtain a wide class of exact, static
metrics. We show that the theory of Yilmaz relates to the pseudo-conformal
sector of our construction. We derive also a unique cosmological (time
dependent) solution of the described type.Comment: Latex, 17 page
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