Decay of a square pulse to Sine-Gordon breathers
We investigate numerically and analytically the existence of thresholds for the production of Sine-Gordon single and multiple breathers from simple initial pulses.
cond-mat.other↗
arXiv subjects
G. Ka"lbermann
Publications and source records attributed to G. Ka"lbermann.
A differential equation for the Saffman-Taylor finger
We develop a stream function approach for the horizontal Hele-Shaw, Saffman-Taylor finger. The model yields a nonlinear time-dependent differential equation. The finger widths derived from the equation are $1>λ>\frac{1}{\sqrt{5}}$, in units of half the width of the Hele-Shaw cell, in accordance with observation. The equation contains the correct dispersion relation for the creation of the finger instability. In an accompanying paper the stationary solutions of the equation are found numerically.
cond-mat.soft↗
Stationary finger solutions in the Hele-Shaw cell
We solve numerically the nonlinear differential equation for the Hele-Shaw, Saffman-Taylor problem derived in the preceding work. Stationary solutions with no free phenomenological parameters are found to fit the measured patterns. The calculated finger half-widths as a function of the physical parameters of the cell, compare satisfactorily with experiment.
cond-mat.soft↗
A Helium nanodrop bouncing off a wall
We investigate numerically the quantum collision between a stable Helium nanodrop and an infinitely hard wall in one dimension. The scattering outcome is compared to the same event omitting the quantum pressure. Only the quantum process reflects the effect of diffraction of wave packets in space and time.
quant-ph↗