3,985 research outputs found
Thermal entanglement in a two-spin-qutrit system under a nonuniform external magnetic field
The thermal entanglement in a two-spin-qutrit system with two spins coupled
by exchange interaction under a magnetic field in an arbitrary direction is
investigated. Negativity, the measurement of entanglement, is calculated. We
find that for any temperature the evolvement of negativity is symmetric with
respect to magnetic field. The behavior of negativity is presented for four
different cases. The results show that for different temperature, different
magnetic field give maximum entanglement. Both the parallel and antiparallel
magnetic field cases are investigated qualitatively (not quantitatively) in
detail, we find that the entanglement may be enhanced under an antiparallel
magnetic field.Comment: 2 eps figure
Thermal entanglement in a two-qubit Heisenberg XXZ spin chain under an inhomogeneous magnetic field
The thermal entanglement in a two-qubit Heisenberg \emph{XXZ} spin chain is
investigated under an inhomogeneous magnetic field \emph{b}. We show that the
ground-state entanglement is independent of the interaction of
\emph{z}-component . The thermal entanglement at the fixed temperature
can be enhanced when increases. We strictly show that for any
temperature \emph{T} and the entanglement is symmetric with respect to
zero inhomogeneous magnetic field, and the critical inhomogeneous magnetic
field is independent of . The critical magnetic field
increases with the increasing but the maximum entanglement value that the
system can arrive becomes smaller.Comment: 5 EPS figure
Probing crossover from analogous weak antilocalization to localization by an Aharonov-Bohm interferometer on topological insulator surface
We propose a scanning tunneling microscopy Aharonov-Bohm (AB) interferometer
on the surface of a topological insulator (TI) to probe the crossover from
analogous weak antilocalization (WAL) to weak localization (WL) phenomenon via
the AB oscillations in spin-resolved local density of states (LDOS). Based on
our analytical and numerical results, we show that with increasing the energy
gap of TI surface states, the = periodic AB oscillations in
spin-resolved LDOS gradually transit into the periodic oscillations.Comment: 4.2 APL pages, 2 figure
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