513 research outputs found
Distributed entanglement induced by dissipative bosonic media
We describe a scheme with analytic result that allows to generate
steady-state entanglement for two atoms over a dissipative bosonic medium. The
resonant coupling between the mediating bosonic mode and cavity modes produces
three collective atomic decay channels. This dissipative dynamics, together
with the unitary process induced by classical microwave fields, drives the two
atoms to the symmetric or asymmetric entangled steady state conditional upon
the choice of the phases of the microwave fields. The effects on the
steady-state entanglement of off-resonance mediating bosonic modes are
analyzed. The entanglement can be obtained with high fidelity regardless of the
initial state and there is a linear relation in the scaling of the fidelity
with the cooperativity parameter. The fidelity is insensitive to the
fluctuation of the Rabi frequencies of the classical driving fields.Comment: to appear in Europhysics Letter
Nuclear-nuclear interaction mediated by a mechanically controlled nitrogen-vacancy-center spin in diamond
We propose a scheme to achieve nuclear-nuclear indirect interactions mediated
by a mechanically driven nitrogen-vacancy (NV) center in diamond. Here we
demonstrate two-qubit entangling gates and quantum-state transfer between two
carbon nuclei in diamond. In such a system, the NV center interacts with a
nearby nuclear spin via a dipole-dipole interaction. Under the quantum Zeno
condition, the scheme is robust against decoherence caused by coupling between
the NV center (nuclear spins) and the environment. Conveniently, precise
control of dipole coupling is not required so this scheme is insensitive to
fluctuating positions of the nuclear spins and the NV center. Our scheme
provides a general blueprint for multi-nuclear-spin gates and for multi-party
communication in a polygon geometry with each vertex occupied by a nuclear
spin.Comment: 11 pages, 8 figure
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