25,173 research outputs found
A discrete time-dependent method for metastable atoms in intense fields
The full-dimensional time-dependent Schrodinger equation for the electronic
dynamics of single-electron systems in intense external fields is solved
directly using a discrete method.
Our approach combines the finite-difference and Lagrange mesh methods. The
method is applied to calculate the quasienergies and ionization probabilities
of atomic and molecular systems in intense static and dynamic electric fields.
The gauge invariance and accuracy of the method is established. Applications to
multiphoton ionization of positronium and hydrogen atoms and molecules are
presented. At very high intensity above saturation threshold, we extend the
method using a scaling technique to estimate the quasienergies of metastable
states of the hydrogen molecular ion. The results are in good agreement with
recent experiments.Comment: 10 pages, 9 figure, 4 table
Recommended from our members
Fine-Scale Variations in Eucritic Pyroxene FeO/MnO: Process vs. Provenance.
Most asteroidal igneous rocks are eucrite-like basalts and gabbros, composed mostly of ferroan low- and high-Ca pyroxenes and calcic plagioclase, plus smaller amounts of silica (most commonly tridymite), ilmenite, chromite, troilite, Ca-phosphate, metal and sometimes ferroan olivine. Eucrite-like mafic rocks are fragments of the crusts of differentiated asteroids, and most are likely from 4 Vesta
Formation and kinetics of transient metastable states in mixtures under coupled phase ordering and chemical demixing
We present theory and simulation of simultaneous chemical demixing and phase
ordering in a polymer-liquid crystal mixture in conditions where isotropic-
isotropic phase separation is metastable with respect to isotropic-nematic
phase transition. It is found that mesophase formation proceeds by a transient
metastable phase that surround the ordered phase, and whose lifetime is a
function of the ratio of diffusional to orientational mobilities. It is shown
that kinetic phase ordering in polymer-mesogen mixtures is analogous to kinetic
crystallization in polymer solutions.Comment: 17 pages, 5 figures accepted for publication in EP
Quench dynamics of topological quantum phase transition in Wen-plaquette model
We study the quench dynamics of the topological quantum phase transition in
the two-dimensional transverse Wen-plaquette model, which has a phase
transition from a Z2 topologically ordered to a spin-polarized state. By
mapping the Wen-plaquette model onto a one-dimensional quantum Ising model, we
calculate the expectation value of the plaquette operator Fi during a slowly
quenching process from a topologically ordered state. A logarithmic scaling law
of quench dynamics near the quantum phase transition is found, which is
analogous to the well-known static critical behavior of the specific heat in
the one-dimensional quantum Ising model.Comment: 8 pages, 5 figures,add new conten
Inhomogeneous electronic structure probed by spin-echo experiments in the electron doped high-Tc superconductor Pr_{1.85}Ce_{0.15}CuO_{4-y}
63Cu nuclear magnetic resonance (NMR) spin-echo decay rate (T_2^{-1})
measurements are reported for the normal and superconducting states of a single
crystal of Pr_{1.85}Ce_{0.15}CuO_{4-y} (PCCO) in a magnetic field B_0=9T over
the temperature range 2K<T<200K. The spin-echo decay rate is
temperature-dependent for T<55K, and has a substantial dependence on the radio
frequency (rf) pulse parameters below T~25K. This dependence indicates that
T_2^{-1} is strongly effected by a local magnetic field distribution that can
be modified by the rf pulses, including ones that are not at the nuclear Larmor
frequency. The low-temperature results are consistent with the formation of a
static inhomogeneous electronic structure that couples to the rf fields of the
pulses.Comment: 4 pages, 4 figure
Statistical Properties of Share Volume Traded in Financial Markets
We quantitatively investigate the ideas behind the often-expressed adage `it
takes volume to move stock prices', and study the statistical properties of the
number of shares traded for a given stock in a fixed time
interval . We analyze transaction data for the largest 1000 stocks
for the two-year period 1994-95, using a database that records every
transaction for all securities in three major US stock markets. We find that
the distribution displays a power-law decay, and that the
time correlations in display long-range persistence. Further, we
investigate the relation between and the number of transactions
in a time interval , and find that the long-range
correlations in are largely due to those of . Our
results are consistent with the interpretation that the large equal-time
correlation previously found between and the absolute value of
price change (related to volatility) are largely due to
.Comment: 4 pages, two-column format, four figure
Anomalies and Hawking radiation from the Reissner-Nordstr\"om black hole with a global monopole
We extend the work by S. Iso, H. Umetsu and F. Wilczek [Phys. Rev. Lett. 96
(2006) 151302] to derive the Hawking flux via gauge and gravitational anomalies
of a most general two-dimensional non-extremal black hole space-time with the
determinant of its diagonal metric differing from the unity () and use it to investigate Hawking radiation from the Reissner-Nordstrom
black hole with a global monopole by requiring the cancellation of anomalies at
the horizon. It is shown that the compensating energy momentum and gauge fluxes
required to cancel gravitational and gauge anomalies at the horizon are
precisely equivalent to the -dimensional thermal fluxes associated with
Hawking radiation emanating from the horizon at the Hawking temperature. These
fluxes are universally determined by the value of anomalies at the horizon.Comment: 18 pages, 0 figure. 1 footnote and 4 new reference adde
Mutual-Chern-Simons effective theory of doped antiferromagnets
A mutual-Chern-Simons Lagrangian is derived as a minimal field theory
description of the phase-string model for doped antiferromagnets. Such an
effective Lagrangian is shown to retain the full symmetries of parity,
time-reversal, and global SU(2) spin rotation, in contrast to conventional
Chern-Simons theories where first two symmetries are usually broken. Two
ordered phases, i.e., antiferromagnetic and superconducting states, are found
at low temperatures as characterized by dual Meissner effects and dual flux
quantization conditions due to the mutual-Chern-Simons gauge structure. A dual
confinement in charge/spin degrees of freedom occurs such that no true
spin-charge separation is present in these ordered phases, but the spin-charge
separation/deconfinement serves as a driving force in the unconventional phase
transitions of these ordered states to disordered states.Comment: 16 pages, 2 figures; published versio
- …