INVESTIGADORES
BRAGAS Andrea Veronica
artículos
Título:
Control of spin dynamics with laser pulses: Generation of entangled states of donor-bound electrons in a Cd1-x Mnx Te quantum well
Autor/es:
J. M. BAO; A. V. BRAGAS; J. K. FURDYNA; R. MERLIN
Revista:
PHYSICAL REVIEW B - CONDENSED MATTER AND MATERIALS PHYSICS
Referencias:
Año: 2005 vol. 71 p. 453141 - 4531413
ISSN:
0163-1829
Resumen:
A quantum-mechanical many-particle system may exhibit nonlocal behavior in that measurements performed
on one of the particles can affect a second one that is far apart. These so-called entangled states are
crucial for the implementation of quantum information protocols and gates for quantum computation. Here, we
use ultrafast optical pulses and coherent pump-probe techniques to create and control spin entangled states in
an ensemble of up to three non-interacting electrons bound to donors in a Cd1−xMnxTe quantum well. Our
method, relying on the exchange interaction between optically excited excitons and the paramagnetic impurities,
can in principle be applied to entangle an arbitrarily large number of electrons. A microscopic theory of
impulsive stimulated Raman scattering and a model for multi-spin entanglement are presented. The signature
of entanglement is the observation of overtones of donor spin-flips in the differential reflectivity of the probe
pulse. Results are shown for resonant excitation of localized excitons below the gap, and above the gap where
the signatures of entanglement are significantly enhanced. Data is also presented on the generation of coherent
excitations of antiferromagnetically coupled manganese pairs, folded acoustic phonons, exciton Zeeman beats
and entanglement involving two Mn+2 ions.1−xMnxTe quantum well. Our
method, relying on the exchange interaction between optically excited excitons and the paramagnetic impurities,
can in principle be applied to entangle an arbitrarily large number of electrons. A microscopic theory of
impulsive stimulated Raman scattering and a model for multi-spin entanglement are presented. The signature
of entanglement is the observation of overtones of donor spin-flips in the differential reflectivity of the probe
pulse. Results are shown for resonant excitation of localized excitons below the gap, and above the gap where
the signatures of entanglement are significantly enhanced. Data is also presented on the generation of coherent
excitations of antiferromagnetically coupled manganese pairs, folded acoustic phonons, exciton Zeeman beats
and entanglement involving two Mn+2 ions.+2 ions.