28 research outputs found
Thermal entanglement and correlated coherence in two coupled double quantum dots systems
In this work, we investigate the thermal quantum correlations in two coupled
double semiconductor charge qubits. This is carried out by deriving analytical
expressions for both the thermal concurrence and the correlated coherence. We
study, in detail, the effects of the tunneling parameters, the Coulomb
interaction and the temperature on the thermal entanglement and on the
correlated coherence. It is found that the Coulomb potential plays an important
role in the thermal entanglement and in the correlated coherence of the system.
The results also indicate that the Coulomb potential can be used for
significant enhancement of the thermal entanglement and quantum coherence. One
interesting aspect is that the correlated coherence capture all the thermal
entanglement at low temperatures, i.e, the local coherences are totally
transferred to the thermal entanglement. Finally, we focus on the role played
by thermal entanglement and the correlated coherence responsible for quantum
correlations. We show that in all cases, the correlated coherence is more
robust than the thermal entanglement so that quantum algorithms based only on
correlated coherence may be more robust than those based on entanglement. Our
results also show that the entanglement can be tuned by varying the Coulomb
interaction between electrons.Comment: 7 pages, 8 figure
Quantum motion of a spinless particle in curved space: A viewpoint of scattering theory
In this work, we study the scattering of a spinless charged particle
constrained to move on a curved surface in the presence of the Aharonov-Bohm
potential. We begin with the equations of motion for the surface and transverse
dynamics previously obtained in the literature (Ferrari G. and Cuoghi G., Phys.
Rev. Lett. \textbf{100}, 230403 (2008)) and describe the surface with
non-trivial curvature in terms of linear defects such as dislocations and
disclinations. Expressions for the modified phase shift, S--matrix and
scattering amplitude are determined by applying a suitable boundary condition
at the origin, which comes from the self-adjoint extension theory. We also
discuss the presence of a bound state obtained from the pole of the S--matrix.
Finally, we claim that the bound state, the additional scattering and the
dependence of the scattering amplitude with energy are solely due to the
curvature effects.Comment: 9 pages, 1 figur