338 research outputs found
Distribution of resonance widths in localized tight-binding models
We numerically analyze the distribution of scattering resonance widths in
one- and quasi-one dimensional tight binding models, in the localized regime.
We detect and discuss an algebraic decay of the distribution, similar, though
not identical, to recent theoretical predictions.Comment: 18 pages, 6 eps figures, to be published in `The European Physical
Journal B
Spin-polarized quantum transport through a T-shape quantum dot-array: a model of spin splitter
We in this paper study theoretically the spin-polarized quantum transport
through a T-shape quantum dot-array by means of transfer-matrix method along
with the Green^{,}s function technique. Multi-magnetic fields are used to
produce the spin-polarized transmission probabilities and therefore the spin
currents, which are shown to be tunable in a wide range by adjusting the
energy, and the direction-angle of magnetic fields as well. Particularly the
opposite- spin- polarization currents separately flowing out to two electrodes
can be generated and thus the system acts as a spin splitter.Comment: 8 pages, 8 figure
Strange attractor simulated on a quantum computer
We show that dissipative classical dynamics converging to a strange attractor
can be simulated on a quantum computer. Such quantum computations allow to
investigate efficiently the small scale structure of strange attractors,
yielding new information inaccessible to classical computers. This opens new
possibilities for quantum simulations of various dissipative processes in
nature.Comment: latex 4 pages, 4 figures, research at
http://www.quantware.ups-tlse.fr, one fig and discussion adde
Decay Rates and Survival Probabilities in Open Quantum Systems
We provide the first statistical analysis of the decay rates of strongly
driven 3D atomic Rydberg states. The distribution of the rates exhibits
universal features due to Anderson localization, while universality of the time
dependent decay requires particular initial conditions.Comment: 4 pages, 3 figures, ref. on subjec
Workshop on Next Generation Real-Time Embedded Systems
Front Matter, Table of Contents, Preface, Conference Organizatio
Fractal fluctuations in quantum integrable scattering
We theoretically and numerically demonstrate that completely integrable
scattering processes may exhibit fractal transmission fluctuations, due to
typical spectral properties of integrable systems.
Similar properties also occur with scattering processes in the presence of
strong dynamical localization, thus explaining recent numerical observations of
fractality in the latter class of systems.Comment: revtex, 4 pages, 3 eps figure
Halogen bonding stabilizes a cis-azobenzene derivative in the solid state: A crystallographic study
Crystals of trans- and cis-isomers of a fluorinated azobenzene derivative have been prepared and characterized by single-crystal X-ray diffraction. The presence of F atoms on the aromatic core of the azobenzene increases the lifetime of the metastable cis-isomer, allowing single crystals of the cis-azobenzene to be grown. Structural analysis on the cis-azobenzene, complemented with density functional theory calculations, highlights the active role of the halogen-bond contact (N...I synthon) in promoting the stabilization of the cis-isomer. The presence of a long aliphatic chain on the azobenzene unit induces a phase segregation that stabilizes the molecular arrangement for both the trans- and cis-isomers. Due to the rarity of cis-azobenzene crystal structures in the literature, our paper makes a step towards understanding the role of non-covalent interactions in driving the packing of metastable azobenzene isomers. This is expected to be important in the future rational design of solid-state, photoresponsive materials based on halogen bonding. We show by single-crystal X-ray diffraction studies and computational analysis that halogen bonding can stabilize a metastable cis-azobenzene derivative in the solid state
Coordination networks incorporating halogen-bond donor sites and azobenzene groups
Two Zn coordination networks, [Zn(1)(Py)2]2(2-propanol)n (3) and [Zn(1)2(Bipy)2](DMF)2n (4), incorporating halogen-bond (XB) donor sites and azobenzene groups have been synthesized and fully characterized. Obtaining 3 and 4 confirms that it is possible to use a ligand wherein its coordination bond acceptor sites and XB donor sites are on the same molecular scaffold (i.e., an aromatic ring) without interfering with each other. We demonstrate that XBs play a fundamental role in the architectures and properties of the obtained coordination networks. In 3, XBs promote the formation of 2D supramolecular layers, which, by overlapping each other, allow the incorporation of 2-propanol as a guest molecule. In 4, XBs support the connection of the layers and are essential to firmly pin DMF solvent molecules through I⋯O contacts, thus increasing the stability of the solvated systems
Can quantum fractal fluctuations be observed in an atom-optics kicked rotor experiment?
We investigate the parametric fluctuations in the quantum survival
probability of an open version of the delta-kicked rotor model in the deep
quantum regime. Spectral arguments [Guarneri I and Terraneo M 2001 Phys. Rev. E
vol. 65 015203(R)] predict the existence of parametric fractal fluctuations
owing to the strong dynamical localisation of the eigenstates of the kicked
rotor. We discuss the possibility of observing such dynamically-induced
fractality in the quantum survival probability as a function of the kicking
period for the atom-optics realisation of the kicked rotor. The influence of
the atoms' initial momentum distribution is studied as well as the dependence
of the expected fractal dimension on finite-size effects of the experiment,
such as finite detection windows and short measurement times. Our results show
that clear signatures of fractality could be observed in experiments with cold
atoms subjected to periodically flashed optical lattices, which offer an
excellent control on interaction times and the initial atomic ensemble.Comment: 18 pp, 7 figs., 1 tabl
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