10,298 research outputs found
Universality of Uhrig dynamical decoupling for suppressing qubit pure dephasing and relaxation
The optimal -pulse dynamical decoupling discovered by Uhrig for a
spin-boson mmodel [Phys. Rev. Lett, {\bf 98}, 100504 (2007)] is proved to be
universal in suppressing to the pure dephasing or the longitudinal
relaxation of a qubit (or spin-1/2) coupled to a generic bath in a short-time
evolution of duration . It is also found that for the purpose of suppressing
the longitudinal relaxation, an ideal Uhrig -pulse sequence can be
generalized to a sequence consisting of the ideal one superimposed with
finite-duration pulses satisfying certain symmetry requirements.Comment: 4 pages, 1 figure
Scaling and memory in the return intervals of energy dissipation rate in three-dimensional fully developed turbulence
We study the statistical properties of return intervals between
successive energy dissipation rates above a certain threshold in
three-dimensional fully developed turbulence. We find that the distribution
function scales with the mean return interval as
except for , where the scaling function
has two power-law regimes. The return intervals are short-term and long-term
correlated and possess multifractal nature. The Hurst index of the return
intervals decays exponentially against , predicting that rare extreme
events with are also long-term correlated with the Hurst index
.Comment: 5 pages, 5 figure
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The effect of core-shell engineering on the energy product of magnetic nanometals.
Solution-based growth of magnetic FePt-FeCo (core-shell) nanoparticles with a controllable shell thickness has been demonstrated. The transition from spin canting to exchange coupling of FePt-FeCo core-shell nanostructures leads to a 28% increase in the coercivity (12.8 KOe) and a two-fold enhancement in the energy product (9.11 MGOe)
A Robust and Ultra-Fast Short Circuit Detection in Half-Bridge Using Stray Voltage Capture:Applied in Electromagnetic Suspension
The paper proposes a robust and ultra-fast short circuit detection method based on the voltage dip in the half-bridge due to the presence of stray inductance. For the application of the inverter in electromagnetic suspension, the short circuit is detected in less than 100 ns, which is a promising solution against the Fault Under Load due to a Single-Event Burnout failure type
The effect of baroque music on the PassPoints graphical password
Graphical passwords have been demonstrated to be the possible alternatives to traditional alphanumeric passwords. However, they still tend to follow predictable patterns that are easier to attack. The crux of the problem is users’ memory limitations. Users are the weakest link in password authentication mechanism. It shows that baroque music has positive effects on human memorizing and learning. We introduce baroque music to the PassPoints graphical password scheme and conduct a laboratory study in this paper. Results shown that there is no statistic difference between the music group and the control group without music in short-term recall experiments, both had high recall success rates. But in long-term recall, the music group performed significantly better. We also found that the music group tended to set significantly more complicated passwords, which are usually more resistant to dictionary and other guess attacks. But compared with the control group, the music group took more time to log in both in short-term and long-term tests. Besides, it appears that background music does not work in terms of hotspots
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