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Branching flow -- a phenomenon known for steady wave propagation in two-dimensional weak correlated random potential is also present in the time-dependent Schr\"odinger equation for a single particle in one dimension, moving in a fluctuating random potential. We explore the two-dimensional parameter space of this model using numerical simulations and identify its classical regions, where just one classical parameter is sufficient for its specification, and its quantum region, where such a simplification is not possible. We also identify region of the parameter space where known analytical results of a classical white-noise model are relevant. Qualitative behavior of quantum and classical particle dynamics is discussed in terms of branching time scale and a new time scale related to particle's kinetic energy., Comment: 8 pages, 8 figures

Measurements of surface temperature fields are used to determine the heat transfer by conduction and convection from an inhomogeneously heated metallic tube into environment. For most of the here reported measurements we use a low-cost infra-red camera Seek Thermal, but the results are also compared to measurements done with a professional Fluke Ti20 Thermal imager. The results are interpreted using two simple theoretical models which give estimates of the thermal conductivity of the tube and the heat transfer coefficient between the tube and the environment.

We present theoretical foundations and numerical demonstration of an efficient method for performing time-dependent many-electron simulations for electronic transport. The method employs the concept of stroboscopic wavepacket basis for the description of electrons' dynamics in the semi-infinite leads.The rest of the system can be treated using common propagation schemes for finite electronic systems. We use the implementation of our method to study the time-dependent current response in armchair graphene nano-ribbons (AGNR) with sizes up to 800 atoms described within tight-binding approximation. The character of the time-dependent current is studied for different magnitudes of the bias voltage, variable width and length of AGNRs, different positions of the current measurement, and for full and reduced coupling of the AGNRs to the electrodes., Comment: corrections of typos compared to previous version

We characterize the role of the spin-orbit coupling between electrons and the confining potential of the edge in nonequilibrium 2D homogeneous electronic gas. We derive a simple analytical result for the magnitude of the current induced spin polarization at the edge and prove that it is independent of the details of the confinement edge potential and the electronic density within realistic values of the parameters of the considered models. While the amplitude of the spin accumulation is comparable to the experimental values of extrinsic spin Hall effect in similar samples, the spatial extent of edge induced effect is restricted to the distances of the order of Fermi wavelength ($\sim$ 10nm)., Comment: 7 pages, 5 figures