20,647 research outputs found
Shape-resonance-induced non-FranckāCondon effects in (2+1) resonance enhanced multiphoton ionization of the C 3Ī g state of O2
We show that strong non-FranckāCondon effects observed in (2+1) resonance enhanced multiphoton ionization of the C 3Pig state of O2 are due to the ksigmau shape resonance previously observed in single-photon studies of diatomic molecules. Calculated vibrational branching ratios for the v=2,3 levels of the C 3Ī g state are in reasonable agreement with experiment. Certain discrepancies remain in comparing theoretical results with the measured spectra, and possible electron-correlation effects which underly this are discussed
Critical Temperature and Amplitude Ratios from a Finite-Temperature Renormalization Group
We study \l\f^4 theory using an environmentally friendly finite-temperature
renormalization group. We derive flow equations, using a fiducial temperature
as flow parameter, develop them perturbatively in an expansion free from
ultraviolet and infrared divergences, then integrate them numerically from zero
to temperatures above the critical temperature. The critical temperature, at
which the mass vanishes, is obtained by integrating the flow equations and is
determined as a function of the zero-temperature mass and coupling. We
calculate the field expectation value and minimum of the effective potential as
functions of temperature and derive some universal amplitude ratios which
connect the broken and symmetric phases of the theory. The latter are found to
be in good agreement with those of the three-dimensional Ising model obtained
from high- and low-temperature series expansions.Comment: 14 pages of LaTeX. Postscript figures available upon request form
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Restrictiveness and guidance in support systems
Restrictiveness and guidance have been proposed as methods for improving the performance of users of support systems. In many companies computerized support systems are used in demand forecasting enabling interventions based on management judgment to be applied to statistical forecasts. However, the resulting forecasts are often āsub-optimalā because many judgmental adjustments are made when they are not required. An experiment was used to investigate whether restrictiveness or guidance in a support system leads to more effective use of judgment. Users received statistical forecasts of the demand for products that were subject to promotions. In the restrictiveness mode small judgmental adjustments to these forecasts were prohibited (research indicates that these waste effort and may damage accuracy). In the guidance mode users were advised to make adjustments in promotion periods, but not to adjust in non-promotion periods. A control group of users were not subject to restrictions and received no guidance. The results showed that neither restrictiveness nor guidance led to improvements in accuracy. While restrictiveness reduced unnecessary adjustments, it deterred desirable adjustments and also encouraged over-large adjustments so that accuracy was damaged. Guidance encouraged more desirable system use, but was often ignored. Surprisingly, users indicated it was less acceptable than restrictiveness
Recurrence interval analysis of high-frequency financial returns and its application to risk estimation
We investigate the probability distributions of the recurrence intervals
between consecutive 1-min returns above a positive threshold or
below a negative threshold of two indices and 20 individual stocks in
China's stock market. The distributions of recurrence intervals for positive
and negative thresholds are symmetric, and display power-law tails tested by
three goodness-of-fit measures including the Kolmogorov-Smirnov (KS) statistic,
the weighted KS statistic and the Cram\'er-von Mises criterion. Both long-term
and shot-term memory effects are observed in the recurrence intervals for
positive and negative thresholds . We further apply the recurrence interval
analysis to the risk estimation for the Chinese stock markets based on the
probability , Value-at-Risk (VaR) analysis and VaR analysis
conditioned on preceding recurrence intervals.Comment: 17 pages, 10 figures, 1 tabl
Long-distance entanglement generation with scalable and robust two-dimensional quantum network
We present a protocol for generating entanglement over long distances in a
two-dimensional quantum network based on the surface error-correction code.
This protocol requires a fixed number of quantum memories at each node of the
network and tolerates error rates of up to 1.67% in the quantum channels.Comment: 5 pags, 4 figs. V2: text corrected, discussion on channel losses
added. Accepted by PR
Parental rearing style as a predictor of attachment and psychosocial adjustment during young adulthood
Parental rearing-styles are crucial for psychosocial adjustment both during childhood and adulthood. The current study examined whether: (a) parental rearing-styles predicted psychosocial adjustment in young-adulthood, (b) this relationship was mediated by attachment styles , and ( c ) gender differences occur in these relationships. Two hundred and forty (103 male and 132 female) university students completed measures assessing parental rearing-style , current attachment style, romantic relationship satisfaction, friendship quality, self-esteem, and social competence. Multigroup structural equation modelling, conducted separately by gender, revealed that parental rearing-style predicted psychosocial adjustment during young-adulthood. Further, there was also evidence of gender differences and that self-models and other-models of attachment mediated this relationship. Together, these findings reinforce the importance of perceived parental rearing-style for subsequent psychosocial adjustment
Vibrational state dependence of ionic rotational branching ratios in resonance enhanced multiphoton ionization of CH
We show that rapid evolution of a Rydberg orbital with internuclear distance in a resonance enhanced multiphoton ionization (REMPI) process can have a profound influence on the production of molecular ions in alternative rotational states. This is illustrated by calculations of ionic rotational branching ratios for (2+1ā²) REMPI via the O11 (20.5) branch of the Eā²ā^2Ī£^+(3pĻ) Rydberg state of CH. The rotational propensity rule for ionization changes from ĪN=odd (ĪN=N_+āN_i) at lower vibrational excitation, as expected from the ĪN+l=odd selection rule, to ĪN=even at higher vibrational levels. This effect is expected to be quite general and should be most readily observable in diatomic hydrides
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