arXiv subjects

Peter Bokes

Publications and source records attributed to Peter Bokes.

5 recordsLinked to original sources

arXiv2025

Impact of a tunneling particle on the quantum state of a barrier: two-particle wave-packet model

We investigate the scattering of two distinguishable particles with unequal masses and a mutual short-range interaction with the aim of quantifying the impact of a tunneling ``projectile'' particle on the quantum mechanical state of the ``barrier'' particle. We find that the states of the barrier particle after the tunneling or reflection of the projectile are displaced by a finite distance that is given by the derivative of the phase of the transmission or reflection amplitudes multiplied by factors dependent on particles' masses, respectively. We demonstrate these results on a numerical example with a resonant interaction between a projectile and barrier. Our work demonstrates physical implication of the concept of phase time delay in the form of finite displacements of particles that are, in principle, experimentally measurable.

quant-ph↗

arXiv2022

Quantum and classical branching flow in space and time

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.

quant-ph↗

arXiv2019

Measurement and simulation of a temperature field

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.

physics.app-ph↗

arXiv2014

Wavepacket representation of leads for efficient simulations of time-dependent electronic transport

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.

cond-mat.mtrl-sci↗

arXiv2010

Edge-induced spin polarization in two-dimensional electron gas

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).

cond-mat.mes-hall↗