Volume 129, Issue 16, 28 October 2008
Index of content:
Exact computation and large angular momentum asymptotics of symbols: Semiclassical disentangling of spin networks129(2008); http://dx.doi.org/10.1063/1.3000578View Description Hide Description
Spin networks, namely, the symbols of quantum angular momentumtheory and their generalizations to groups other than SU(2) and to quantum groups, permeate many areas of pure and applied science. The issues of their computation and characterization for large values of their entries are a challenge for diverse fields, such as spectroscopy and quantum chemistry, molecular and condensed matter physics, quantum computing, and the geometry of space time. Here we record progress both in their efficient calculation and in the study of the large asymptotics. For the symbol, a prototypical entangled network, we present and extensively check numerically formulas that illustrate the passage to the semiclassical limit, manifesting both the occurrence of disentangling and the discrete-continuum transition.
129(2008); http://dx.doi.org/10.1063/1.3000393View Description Hide Description
We present a fully quantum mechanical methodology for calculating complex-time correlation functions by evaluating the discretized path integral expression iteratively on a grid selected by a Monte Carlo procedure. Both the grid points and the summations performed in each iteration utilize importance sampling, leading to favorable scaling with the number of particles, while the stepwise evaluation of the integrals circumvents the exponential growth of statistical error with time.
Attosecond nonlinear Fourier transformation spectroscopy of in extreme ultraviolet wavelength region129(2008); http://dx.doi.org/10.1063/1.3006026View Description Hide Description
The interferometric autocorrelation functions of attosecond pulse trains in the time domain were measured by detecting as well as the atomic and molecular fragment ions generated via two-photon absorption of intense vacuum ultraviolet-extreme ultraviolet light by . It was demonstrated that the Fourier transformation of the interferometric autocorrelation functions of the respective fragment ions appearing in a time-of-flight mass spectrum exhibit spectroscopic information in the frequency domain corresponding to the two-photon photofragment excitation spectra of and the double ionization excitation spectrum to form .