1,734 research outputs found
Spin and Orbital Splitting in Ferromagnetic Contacted Single Wall Carbon Nanotube Devices
We observed the coulomb blockade phenomena in ferromagnetic contacting single
wall semiconducting carbon nanotube devices. No obvious Coulomb peaks shift was
observed with existing only the Zeeman splitting at 4K. Combining with other
effects, the ferromagnetic leads prevent the orbital spin states splitting with
magnetic field up to 2 Tesla at 4K. With increasing magnetic field further,
both positive or negative coulomb peaks shift slopes are observed associating
with clockwise and anticlockwise orbital state splitting. The strongly
suppressed/enhanced of the conductance has been observed associating with the
magnetic field induced orbital states splitting/converging
Franck-Condon Physics in A Single Trapped Ion
We propose how to explore the Franck-Condon (FC) physics via a single ion
confined in a spin-dependent potential, formed by the combination of a Paul
trap and a magnetic field gradient. The correlation between electronic and
vibrational degrees of freedom, called as electron-vibron coupling, is induced
by a nonzero gradient. For a sufficiently strong electron-vibron coupling, the
FC blockade of low-lying vibronic transitions takes place. We analyze the
feasibility of observing the FC physics in a single trapped ion, and
demonstrate various potential applications of the ionic FC physics in quantum
state engineering and quantum information processing.Comment: 7 pages, 5 figure
Study of ambiguities in scattering amplitudes
Amplitudes for the reaction are reconstructed from
data on the differential cross section , the recoil
polarization , and on the spin rotation parameter . At low energies,
no data on exist, resulting in ambiguities. An approximation using
and waves leads only to a fair description of the data on
and ; in this case, there are two sets of amplitudes. Including waves,
the data on and are well reproduced by the fit but now,
there are several distinct solutions which describe the data with identical
precision. In the range where the spin rotation parameter was measured,
a full and unambiguous reconstruction of the partial wave amplitudes is
possible. The energy-independent amplitudes are compared to the energy
dependent amplitudes which resulted from a coupled channel fit (BnGa2011-02) to
a large data set including both pion and photo-induced reactions. Significant
deviations are observed. Consistency between energy dependent and energy
independent solutions by choosing the energy independent solution which is
closest to the energy dependent solution. In a second step, the {\it known}
energy dependent solution for low (or high) partial waves is imposed and only
the high (or low) partial waves are fitted leading to smaller uncertainties
Edge spin accumulation in a ballistic regime
We consider a mesoscopic {\it ballistic} structure with Rashba spin-orbit
splitting of the electron spectrum. The ballistic region is attached to the
leads with a voltage applied between them. We calculate the edge spin density
which appears in the presence of a charge current through the structure due to
the difference in populations of electrons coming from different leads.
Combined effect of the boundary scattering and spin precession leads to
oscillations of the edge polarization with the envelope function decaying as a
power law of the distance from the boundary. The problem is solved with the use
of scattering states. The simplicity of the method allows to gain an insight
into the underlaying physics. We clarify the role of the unitarity of
scattering for the problem of edge spin accumulation. In case of a straight
boundary it leads to exact cancellation of all long-wave oscillations of the
spin density. As a result, only the Friedel-like spin density oscillations with
the momentum 2k_F survive. However, this appears to be rather exceptional case.
In general, the smooth spin oscillations with the spin precession length
recover, as it happens, e.g., for the wiggly boundary. We demonstrate also,
that there is no relation between the spin current in the bulk, which is zero
in the considered case, and the edge spin accumulation.Comment: Latex, 6 pages, 2 fig
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