135 research outputs found
Chaotic spin-dependent electron dynamics in a field-driven double dot potential
We study the nonlinear classical dynamics of an electron confined in a double
dot potential and subjected to a spin-orbit coupling and a constant external
magnetic field. It is shown that due to the spin orbit coupling, the energy can
be transferred from the spin to the orbital motion. This naturally heats up the
orbital motion which, due to the presence of the separatrix line in the phase
space of the system, results in a motion of the electron between the dots. It
is shown that depending on the strength of the spin orbit coupling and the
energy of the system, the electronic orbital motion undergoes a transition from
the regular to the chaotic regime.Comment: 15 pages, 5 figure
Thermal entanglement and efficiency of the quantum Otto cycle for the su(1,1) Tavis-Cummings system
The influence of the dynamical Stark shift on the thermal entanglement and
the efficiency of the quantum Otto cycle is studied for the su(1,1)
Tavis-Cummings system. It is shown that the degree of the thermal entanglement
becomes larger as the dynamical Stark shift increases. In contrast, the
efficiency of the Otto cycle is degraded with an increase of the values of
dynamical Stark shift. Expressions for the efficiency coefficient are derived.
Using those expressions we identify the maximal efficiency of the quantum Otto
cycle from the experimentally measured values of the dynamical Stark shiftComment: to appear in J.Phys.
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