229 research outputs found
Oscillating spin-orbit interaction as a source of spin-polarized wave packets in two-terminal nanoscale devices
Ballistic transport through nanoscale devices with time-dependent Rashba-type
spin-orbit interaction (SOI) can lead to spin-polarized wave packets that
appear even for completely unpolarized input. The SOI that oscillates in a
finite domain generates density and spin polarization fluctuations that leave
the region as propagating waves. Particularly, spin polarization has space and
time dependence even in regions without SOI. Our results are based on an
analytic solution of the time-dependent Schr\"odinger equation. The relevant
Floquet quasi-energies that are obtained appear in the energy spectrum of both
the transmitted and reflected waves.Comment: 13 pages, 5 figures (IOP preprint style); v2: 15 pages and 6 figures.
Subsec. 3.4, a figure and new references have been adde
Dynamics of molecular nanomagnets in time-dependent external magnetic fields: Beyond the Landau-Zener-St\"{u}ckelberg model
The time evolution of the magnetization of a magnetic molecular crystal is
obtained in an external time-dependent magnetic field, with sweep rates in the
kT/s range. We present the 'exact numerical' solution of the time dependent
Schr\"{o}dinger equation, and show that the steps in the hysteresis curve can
be described as a sequence of two-level transitions between adiabatic states.
The multilevel nature of the problem causes the transition probabilities to
deviate significantly from the predictions of the Landau-Zener-St\"{u}ckelberg
model. These calculations allow the introduction of an efficient approximation
method that accurately reproduces the exact results. When including phase
relaxation by means of an appropriate master equation, we observe an interplay
between coherent dynamics and decoherence. This decreases the size of the
magnetization steps at the transitions, but does not modify qualitatively the
physical picture obtained without relaxation.Comment: 8 pages, 7 figure
Dynamics of periodic anticrossings: Decoherence, pointer states and hysteresis curves
We consider a strongly driven two-level (spin) system, with a periodic
external field that induces a sequence of avoided level crossings. The spin
system interacts with a bosonic reservoir which leads to decoherence. A
Markovian dynamical equation is introduced without relying on the rotating wave
approximation in the system-external field interaction. We show that the time
evolution of the two-level system is directed towards an incoherent sum of
periodic Floquet states regardless of the initial state and even the type of
the coupling to the environment. Analyzing the time scale of approaching these
time-dependent pointer states, information can be deduced concerning the nature
and strength of the system-environment coupling. The inversion as a function of
the external field is usually multi-valued, and the form of these hysteresis
curves is qualitatively different for low and high temperatures. For moderate
temperatures we found that the series of Landau-Zener-St\"{u}ckelberg-type
transitions still can be used for state preparation, regardless of the
decoherence rate. Possible applications include quantum information processing
and molecular nanomagnets.Comment: 10 pages, 9 slightly reduced quality figures, submitted to PRA; More
details concerning applications to molacular nanomagnets are give
A Case of Rheumatoid Arthritis with Bucillamine-Induced Yellow Nail Syndrome Initially Manifesting as Pulmonary Disease
We report a case of a 67-year-old woman with rheumatoid arthritis with yellow nail syndrome (YNS) that was caused by bucillamine. All three signs (yellow fingernails, lymphatic edema, and bronchiectasis) of YNS manifested, with characteristic timing, first with the nails turning yellow after when bronchiectasis was noticed. We reviewed 10 case reports from Japan and compared the periods until the appearance of yellow nails after starting bucillamine treatment, as well as those until lung disease and leg edema appeared
Reconsidering the multiple criteria decision making problems of construction projects : using advanced visualization and data mining tools
The Effects of Breeding Protocol in C57BL/6J Mice on Adult Offspring Behaviour
Animal experiments have demonstrated that a wide range of prenatal exposures can impact on the behaviour of the offspring. However, there is a lack of evidence as to whether the duration of sire exposure could affect such outcomes. We compared two widely used methods for breeding offspring for behavioural studies. The first involved housing male and female C57Bl/6J mice together for a period of time (usually 10–12 days) and checking for pregnancy by the presence of a distended abdomen (Pair-housed; PH). The second involved daily introduction of female breeders to the male homecage followed by daily checks for pregnancy by the presence of vaginal plugs (Time-mated; TM). Male and female offspring were tested at 10 weeks of age on a behavioural test battery including the elevated plus-maze, hole board, light/dark emergence, forced swim test, novelty-suppressed feeding, active avoidance and extinction, tests for nociception and for prepulse inhibition (PPI) of the acoustic startle response. We found that length of sire exposure (LSE) had no significant effects on offspring behaviour, suggesting that the two breeding protocols do not differentially affect the behavioural outcomes of interest. The absence of LSE effects on the selected variables examined does not detract from the relevance of this study. Information regarding the potential influences of breeding protocol is not only absent from the literature, but also likely to be of particular interest to researchers studying the influence of prenatal manipulations on adult behaviour
- …