We study certain stationary and time-evolution problems of trapped Bose-Einstein condensates using the numerical solution of the Gross-Pitaevskii equation with both spherical and axial symmetries. We consider time-evolution problems initiated by changing the interatomic scattering length or harmonic trapping potential suddenly in a stationary condensate. These changes introduce oscillations in ...

We study the influence of nonequilibrium conditions on the collective diffusion of interacting particles on vicinal surfaces. To this end, we perform Monte Carlo simulations of a lattice-gas model of an ideal stepped surface, where adatoms have nearest-neighbor attractive or repulsive interactions. Applying the Boltzmann-Matano method to spreading density profiles of the adatoms allows the defi...

Two numerical methods are presented for the periodic initial-value problem of the long wave–short wave interaction equations describing the interaction between one long longitudinal wave and two short transverse waves propagating in a generalized elastic medium. The first one is the relaxation method, which is implicit with second-order accuracy in both space and time. The second one is the spl...

A new three-dimensional model of the FEL is presented. A system of scaled, coupled Maxwell–Lorentz equations are derived in the paraxial limit. A minimal number of limiting assumptions are made and the equations are not averaged in the longitudinal direction of common radiation/electron beam propagation, allowing the effects of coherent spontaneous emission and non-localised electron propagatio...

An original technique, Spectral Self-Interference Fluorescence Microscopy (SSFM), can determine the location of fluorescent markers above a reflecting surface with sub-nanometer precision. SSFM was used to resolve the position of a fluorescent marker bound to either the top or the bottom leaflet of a lipid bilayer – the difference in distance is only 4 nm. SSFM is a valuable tool in studying th...

In optics the nonlinear Schrödinger equation (NLSE) which modelizes wave propagation in an optical fiber is mostly solved by the Symmetric Split-Step method. The practical efficiency of the Symmetric Split-Step method is highly dependent on the computational grid points distribution along the fiber, therefore an efficient adaptive step-size control strategy is mandatory. The most common approac...

The Interaction Picture (IP) method is a valuable alternative to Split-step methods for solving certain types of partial differential equations such as the nonlinear Schrödinger equation or the Gross-Pitaevskii equation. Although very similar to the Symmetric Split-step (SS) method in its inner computational structure, the IP method results from a change of unknown and therefore do not involve ...

During side-step cutting, all the monitored muscles were recruited simultaneously reflecting co-contraction. Conversely, during split-step cutting, rectus femoris was initially recruited, followed by synchronous vastii and medial hamstrings onset and then lateral hamstring muscle onset. Although there were subtle differences in onset, the hamstrings ceased activity earlier than the quadriceps m...

This paper describes a method to detect errors in written text which requires no manual work. The method used is to simply annotate a lot of errors in written text and train an off-theshelf machine learning implementation to recognize such errors. To avoid manual annotation synthetically created errors are used for training. The method is evaluated on erroneously split compounds and word order ...

A standard problem within universities is that of teaching space allocation which can be thought of as the assignment of rooms and times to various teaching activities. The focus is usually on courses that are expected to fit into one room. However, it can also happen that the course will need to be broken up, or ‘split’, into multiple sections. A lecture might be too large to fit into any one ...