1,782 research outputs found
Analytic solution of charge density of single wall carbon nanotube in conditions of field electron emission
We derived the analytic solution of induced electrostatic potential along
single wall carbon nanotubes. Under the hypothesis of constant density of
states in the charge-neutral level, we are able to obtain the linear density of
excess charge in an external field parallel to the tube axis.Comment: 4 pages, 3 figure
Quantum state transmission via a spin ladder as a robust data bus
We explore the physical mechanism to coherently transfer the quantum
information of spin by connecting two spins to an isotropic antiferromagnetic
spin ladder system as data bus. Due to a large spin gap existing in such a
perfect medium, the effective Hamiltonian of the two connected spins can be
archived as that of Heisenberg type, which possesses a ground state with
maximal entanglement. We show that the effective coupling strength is inversely
proportional to the distance of the two spins and thus the quantum information
can be transferred between the two spins separated by a longer distance, i.e.
the characteristic time of quantum state transferring linearly depends on the
distance.Comment: 7 pages, 5 figures, 1 tabl
Coherent heteronuclear spin dynamics in an ultracold spin-1 mixture
We report the observation of coherent heteronuclear spin dynamics driven by
inter-species spin-spin interaction in an ultracold spinor mixture, which
manifests as periodical and well correlated spin oscillations between two
atomic species. In particular, we investigate the magnetic field dependence of
the oscillations and find a resonance behavior which depends on {\em both} the
linear and quadratic Zeeman effects and the spin-dependent interaction. We also
demonstrate a unique knob for controlling the spin dynamics in the spinor
mixture with species-dependent vector light shifts. Our finds are in agreement
with theoretical simulations without any fitting parameters.Comment: 13 pages including the supplementary materia
Fusion Reactivities with Drift bi-Maxwellian Ion Velocity Distributions
The calculation of fusion reactivity involves a complex six-dimensional
integral that takes into account the fusion cross-section and velocity
distributions of two reactants. However, a more simplified one-dimensional
integral form can be useful in certain cases, such as for studying fusion yield
or diagnosing ion energy spectra. This simpler form has been derived in a few
special cases, such as for a combination of two Maxwellian distributions, a
beam-Maxwellian combination, and a beam-target combination, and can greatly
reduce computational costs. In this study, it is shown that the reactivity for
two drift bi-Maxwellian reactants with different drift velocities,
temperatures, and anisotropies can also be reduced to a one-dimensional form,
unifying existing derivations into a single expression. This result is used to
investigate the potential enhancement of fusion reactivity due to the
combination of beam and temperature anisotropies. For relevant parameters in
fusion energy, the enhancement factor can be larger than 20\%, which is
particularly significant for proton-boron (p-B11) fusion, as this factor can
have a significant impact on the Lawson fusion gain criteria.Comment: 12 pages, 10 figures, 1 supplementary material for detail derivatio
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