1,796 research outputs found
Spin-relaxation anisotropy in a nanowire quantum dot with strong spin-orbit coupling
We study the impacts of the magnetic field direction on the spin-manipulation
and the spin-relaxation in a one-dimensional quantum dot with strong spin-orbit
coupling. The energy spectrum and the corresponding eigenfunctions in the
quantum dot are obtained exactly. We find that no matter how large the
spin-orbit coupling is, the electric-dipole spin transition rate as a function
of the magnetic field direction always has a periodicity. However, the
phonon-induced spin relaxation rate as a function of the magnetic field
direction has a periodicity only in the weak spin-orbit coupling regime,
and the periodicity is prolonged to in the strong spin-orbit coupling
regime.Comment: 8 pages, 4 figure
Rigid vortices in MgB2
Magnetic relaxation of high-pressure synthesized MgB bulks with different
thickness is investigated. It is found that the superconducting dia-magnetic
moment depends on time in a logarithmic way; the flux-creep activation energy
decreases linearly with the current density (as expected by Kim-Anderson
model); and the activation energy increases linearly with the thickness of
sample when it is thinner than about 1 mm. These features suggest that the
vortices in the MgB are rather rigid, and the pinning and creep can be well
described by Kim-Anderson model.Comment: Typo corrected & reference adde
Probing the states through radiative decays
In this work, we have adopted the spin rearrangement scheme in the heavy
quark limit and extensively investigated three classes of the radiative decays:
, , , corresponding to the
electromagnetic transitions between one molecular state and bottomonium, one
bottomonium and molecular state, and two molecular states respectively. We also
extend the same formalism to study the radiative decays of the molecular states
with hidden charm. We have derived some model independent ratios when the
initial or final states belong to the same spin flavor multiplet. Future
experimental measurement of these ratios will test the molecular picture and
explore the underlying structures of the states.Comment: 21 pages, 10 tables Accepted by Phys.Rev.
Spin-Orbit Interaction Enabled High-Fidelity Two-Qubit Gates
We study the implications of spin-orbit interaction (SOI) for two-qubit gates
(TQGs) in semiconductor spin qubit platforms. The exchange interaction
governing qubit pairs is anisotropic under SOI, posing a problem for
conventional TQGs derived under the Heisenberg exchange. After developing a
concise form of the effective two-qubit Hamiltonian under SOI, we use it to
derive properties of rotating-frame evolution. Two main observations are made.
First, in contrary to past belief, we find that an appropriate amount of SOI
can significantly enhance the controlled-phase gate fidelity compared to the
no-SOI case. Second, SOI enables novel two-qubit dynamics, that are
conventionally inaccessible through DC evolution, such as the reflection gate
and the controlled-not gate
A Novel Rough Set Model in Generalized Single Valued Neutrosophic Approximation Spaces and Its Application
In this paper, we extend the rough set model on two different universes in intuitionistic fuzzy approximation spaces to a single-valued neutrosophic environment
2,4-Dichloro-6-nitroÂbenzoic acid
The title compound, C7H3Cl2NO4, was prepared by the reaction of 2,4-dichloro-6-nitroÂtoluene with 20% HNO3 solution at 430 K. The carboxyl and nitro groups are twisted by 82.82 (12) and 11.9 (2)°, respectively, with respect to the benzene ring. The crystal structure is stabilized by O—H⋯O hydrogen bonding between carboxyl groups and weak C—H⋯O hydrogen bonding between the nitro group and the benzene ring of an adjacent molÂecule
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