4,504 research outputs found
Multiphoton inner-shell ionization of the carbon atom
We apply time-dependent R-matrix theory to study inner-shell ionization of C
atoms in ultra-short high-frequency light fields with a photon energy between
170 and 245 eV. At an intensity of 10 W/cm, ionization is dominated
by single-photon emission of a electron, with two-photon emission of a
1s electron accounting for about 2-3\% of all emission processes, and
two-photon emission of contributing about 0.5-1\%. Three-photon
emission of a 1s electron is estimated to contribute about 0.01-0.03\%. Around
a photon energy of 225 eV, two-photon emission of a 1s electron, leaving C
in either 1s2s2p or 1s2p is resonantly enhanced by intermediate
1s2s2p states. The results demonstrate the capability of time-dependent
R-matrix theory to describe inner-shell ionization processes including
rearrangement of the outer electrons.Comment: 7 pages, 2 figures, 2 table
Angular distributions in two-colour two-photon ionization of He
We present R-Matrix with time dependence (RMT) calculations for the
photoionization of helium irradiated by an EUV laser pulse and an overlapping
IR pulse with an emphasis on the anisotropy parameters of the sidebands
generated by the dressing laser field. We investigate how these parameters
depend on the amount of atomic structure included in the theoretical model for
two-photon ionization. To verify the accuracy of the RMT approach, our
theoretical results are compared with experiment.Comment: 8 pages, 4 figures, 1 tabl
Electron dynamics in the carbon atom induced by spin-orbit interaction
We use R-Matrix theory with Time dependence (RMT) to investigate multiphoton
ionization of ground-state atomic carbon with initial orbital magnetic quantum
number =0 and =1 at a laser wavelength of 390 nm and peak intensity
of 10 W cm. Significant differences in ionization yield and
ejected-electron momentum distribution are observed between the two values for
. We use our theoretical results to model how the spin-orbit interaction
affects electron emission along the laser polarization axis. Under the
assumption that an initial C atom is prepared at zero time delay with ,
the dynamics with respect to time delay of an ionizing probe pulse modelled
using RMT theory is found to be in good agreement with available experimental
data.Comment: 8 pages, 5 figure
An Extension of the Fluctuation Theorem
Heat fluctuations are studied in a dissipative system with both mechanical
and stochastic components for a simple model: a Brownian particle dragged
through water by a moving potential. An extended stationary state fluctuation
theorem is derived. For infinite time, this reduces to the conventional
fluctuation theorem only for small fluctuations; for large fluctuations, it
gives a much larger ratio of the probabilities of the particle to absorb rather
than supply heat. This persists for finite times and should be observable in
experiments similar to a recent one of Wang et al.Comment: 12 pages, 1 eps figure in color (though intelligible in black and
white
Analytical approach to soliton ratchets in asymmetric potentials
We use soliton perturbation theory and collective coordinate ansatz to
investigate the mechanism of soliton ratchets in a driven and damped asymmetric
double sine-Gordon equation. We show that, at the second order of the
perturbation scheme, the soliton internal vibrations can couple {\it
effectively}, in presence of damping, to the motion of the center of mass,
giving rise to transport. An analytical expression for the mean velocity of the
soliton is derived. The results of our analysis confirm the internal mode
mechanism of soliton ratchets proposed in [Phys. Rev. E {\bf 65} 025602(R)
(2002)].Comment: 9 figures. Submitted to Phys. Rev.
Search for universality in one-dimensional ballistic annihilation kinetics
We study the kinetics of ballistic annihilation for a one-dimensional ideal
gas with continuous velocity distribution. A dynamical scaling theory for the
long time behavior of the system is derived. Its validity is supported by
extensive numerical simulations for several velocity distributions. This leads
us to the conjecture that all the continuous velocity distributions \phi(v)
which are symmetric, regular and such that \phi(0) does not vanish, are
attracted in the long time regime towards the same Gaussian distribution and
thus belong to the same universality class. Moreover, it is found that the
particle density decays as n(t)~t^{-\alpha}, with \alpha=0.785 +/- 0.005.Comment: 8 pages, needs multicol, epsf and revtex. 8 postscript figures
included. Submitted to Phys. Rev. E. Also avaiable at
http://mykonos.unige.ch/~rey/publi.html#Secon
Analisis Spasial Pengaruh Dinamika Suhu Muka Laut Terhadap Distribusi Curah Hujan Di Sulawesi Utara
Telah dilakukan analisis terhadap distribusi curah hujan yang dipengaruhi oleh dinamika suhu muka laut untuk mengetahui hubungan distribusi curah hujan dan dinamika suhu muka laut di Sulawesi Utara, serta telah dibuat peta spasial hubungan distribusi curah hujan dengan dinamika suhu muka laut menggunakan ArcMap 9.3. Analisis yang dilakukan menggunakan data curah hujan bulanan selama 10 tahun dari 5 stasiun BMKG dan 10 pos hujan kerjasama di Sulawesi Utara, dan data dinamika suhu muka laut berdasarkan nilai Indeks Osilasi Selatan dengan metode korelasi. Hasil penelitian diperoleh nilai korelasi positif antara 0,50 hingga 0,90 terjadi pada periode tiga bulanan yaitu Agustus-September-Oktober pada seluruh wilayah pengamatan.Analysis of the precipitation that caused by the dynamics of sea surface temperature has been made to find the correlation between the precipitation and the dynamics of sea surface temperature, with its spatial map of the correlation between precipitation and the dynamics of sea surface temperature using ArcMap 9.3. The analysis use the monthly rainfall data for 10 years from 5 BMKG Stations and 10 rain-gauge network in North Sulawesi, and Southern Oscillation Index monthly value using correlation method. The result of this research is the positive correlation between 1,50 to 0,90 occur in the period of August-September-October
Supersymetry on the Noncommutative Lattice
Built upon the proposal of Kaplan et.al. [hep-lat/0206109], we construct
noncommutative lattice gauge theory with manifest supersymmetry. We show that
such theory is naturally implementable via orbifold conditions generalizing
those used by Kaplan {\sl et.al.} We present the prescription in detail and
illustrate it for noncommutative gauge theories latticized partially in two
dimensions. We point out a deformation freedom in the defining theory by a
complex-parameter, reminiscent of discrete torsion in string theory. We show
that, in the continuum limit, the supersymmetry is enhanced only at a
particular value of the deformation parameter, determined solely by the size of
the noncommutativity.Comment: JHEP style, 1+22 pages, no figure, v2: two references added, v3:
three more references adde
Conformal regularization of Einstein's field equations
To study asymptotic structures, we regularize Einstein's field equations by
means of conformal transformations. The conformal factor is chosen so that it
carries a dimensional scale that captures crucial asymptotic features. By
choosing a conformal orthonormal frame we obtain a coupled system of
differential equations for a set of dimensionless variables, associated with
the conformal dimensionless metric, where the variables describe ratios with
respect to the chosen asymptotic scale structure. As examples, we describe some
explicit choices of conformal factors and coordinates appropriate for the
situation of a timelike congruence approaching a singularity. One choice is
shown to just slightly modify the so-called Hubble-normalized approach, and one
leads to dimensionless first order symmetric hyperbolic equations. We also
discuss differences and similarities with other conformal approaches in the
literature, as regards, e.g., isotropic singularities.Comment: New title plus corrections and text added. To appear in CQ
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