125 research outputs found
Suppression of Quantum Scattering in Strongly Confined Systems
We demonstrate that scattering of particles strongly interacting in three
dimensions (3D) can be suppressed at low energies in a quasi-one-dimensional
(1D) confinement. The underlying mechanism is the interference of the s- and
p-wave scattering contributions with large s- and p-wave 3D scattering lengths
being a necessary prerequisite. This low-dimensional quantum scattering effect
might be useful in "interacting" quasi-1D ultracold atomic gases, guided atom
interferometry, and impurity scattering in strongly confined quantum wire-based
electronic devices.Comment: 3 figs, Phys. Rev. Lett. (early November issue
Differential cross sections for muonic atom scattering from hydrogenic molecules
The differential cross sections for low-energy muonic hydrogen atom
scattering from hydrogenic molecules are directly expressed by the
corresponding amplitudes for muonic atom scattering from hydrogen-isotope
nuclei. The energy and angular dependence of these three-body amplitudes is
thus taken naturally into account in scattering from molecules, without
involving any pseudopotentials. Effects of the internal motion of nuclei inside
the target molecules are included for every initial rotational-vibrational
state. These effects are very significant as the considered three-body
amplitudes often vary strongly within the energy interval eV.
The differential cross sections, calculated using the presented method, have
been successfully used for planning and interpreting many experiments in
low-energy muon physics. Studies of nuclear capture in and the
measurement of the Lamb shift in atoms created in H gaseous targets
are recent examples.Comment: 21 pages, 13 figures, submitted to Phys. Rev.
Resonant d-wave scattering in harmonic waveguides
We observe and analyze d-wave resonant scattering of bosons in tightly
confining harmonic waveguides. It is shown that the d-wave resonance emerges in
the quasi-1D regime as an imprint of a 3D d-wave shape resonance. A scaling
relation for the position of the d-wave resonance is provided. By changing the
trap frequency, ultracold scattering can be continuously tuned from s-wave to
d-wave resonant behavior. The effect can be utilized for the realization of
ultracold atomic gases interacting via higher partial waves and opens a novel
possibility for studying strongly correlated atomic systems beyond s-wave
physics.Comment: 6 pages, 9 figure
Multi-Channel Atomic Scattering and Confinement-Induced Resonances in Waveguides
We develop a grid method for multi-channel scattering of atoms in a waveguide
with harmonic confinement. This approach is employed to extensively analyze the
transverse excitations and deexcitations as well as resonant scattering
processes. Collisions of identical bosonic and fermionic as well as
distinguishable atoms in harmonic traps with a single frequency
permitting the center-of-mass (c.m.) separation are explored in depth. In the
zero-energy limit and single mode regime we reproduce the well-known
confinement-induced resonances (CIRs) for bosonic, fermionic and heteronuclear
collisions. In case of the multi-mode regime up to four open transverse
channels are considered. Previously obtained analytical results are extended
significantly here. Series of Feshbach resonances in the transmission behaviour
are identified and analyzed. The behaviour of the transmission with varying
energy and scattering lengths is discussed in detail. The dual CIR leading to a
complete quantum suppression of atomic scattering is revealed in multi-channel
scattering processes. Possible applications include, e.g., cold and ultracold
atom-atom collisions in atomic waveguides and electron-impurity scattering in
quantum wires.Comment: 35 pages, 18 figure
Wave packet evolution approach to ionization of hydrogen molecular ion by fast electrons
The multiply differential cross section of the ionization of hydrogen
molecular ion by fast electron impact is calculated by a direct approach, which
involves the reduction of the initial 6D Schr\"{o}dinger equation to a 3D
evolution problem followed by the modeling of the wave packet dynamics. This
approach avoids the use of stationary Coulomb two-centre functions of the
continuous spectrum of the ejected electron which demands cumbersome
calculations. The results obtained, after verification of the procedure in the
case atomic hydrogen, reveal interesting mechanisms in the case of small
scattering angles.Comment: 7 pages, 8 Postscript figure
The District Heating in the Context of the Active Consumers Development in Smart Energy Systems
The paper defines the main factors of the smart energy systems that influence on the district heating. Noted increase in the regulatory impact of electric energy system on the district heating and increase in roles of the distribution and consumption of thermal energy. Urban population and other consumers of energy become equal partners of the utilities and acquire the status of "active" consumers. The heating supply companies need to develop a new model of management of heating regimes with dynamic synchronization with energy system and "active" consumers. One of the most important conditions of the achievement of the cost reduction, reliability and quality increase in community facilities is active consumer's behavior
- …