255 research outputs found
Selective Control of the Symmetric Dicke Subspace in Trapped Ions
We propose a method of manipulating selectively the symmetric Dicke subspace
in the internal degrees of freedom of N trapped ions. We show that the direct
access to ionic-motional subspaces, based on a suitable tuning of
motion-dependent AC Stark shifts, induces a two-level dynamics involving
previously selected ionic Dicke states. In this manner, it is possible to
produce, sequentially and unitarily, ionic Dicke states with increasing
excitation number. Moreover, we propose a probabilistic technique to produce
directly any ionic Dicke state assuming suitable initial conditions.Comment: 5 pages and 1 figure. New version with minor changes and added
references. Accepted in Physical Review
Field squeeze operators in optical cavities with atomic ensembles
We propose a method of generating unitarily single and two-mode field
squeezing in an optical cavity with an atomic cloud. Through a suitable laser
system, we are able to engineer a squeeze field operator decoupled from the
atomic degrees of freedom, yielding a large squeeze parameter that is scaled up
by the number of atoms, and realizing degenerate and non-degenerate parametric
amplification. By means of the input-output theory we show that ideal squeezed
states and perfect squeezing could be approached at the output. The scheme is
robust to decoherence processes.Comment: Four pages and one figure. Accepted in Physical Review Letter
Dynamics of Entanglement Transfer Through Multipartite Dissipative Systems
We study the dynamics of entanglement transfer in a system composed of two
initially correlated three-level atoms, each located in a cavity interacting
with its own reservoir. Instead of tracing out reservoir modes to describe the
dynamics using the master equation approach, we consider explicitly the
dynamics of the reservoirs. In this situation, we show that the entanglement is
completely transferred from atoms to reservoirs. Although the cavities mediate
this entanglement transfer, we show that under certain conditions, no
entanglement is found in cavities throughout the dynamics. Considering the
entanglement dynamics of interacting and non-interacting bipartite subsystems,
we found time windows where the entanglement can only flow through interacting
subsystems, depending on the system parameters.Comment: 8 pages, 11 figures, publishe in Physical Review
Effective Quantum Dynamics of Interacting Systems with Inhomogeneous Coupling
We study the quantum dynamics of a single mode/particle interacting
inhomogeneously with a large number of particles and introduce an effective
approach to find the accessible Hilbert space where the dynamics takes place.
Two relevant examples are given: the inhomogeneous Tavis-Cummings model (e.g.,
N atomic qubits coupled to a single cavity mode, or to a motional mode in
trapped ions) and the inhomogeneous coupling of an electron spin to N nuclear
spins in a quantum dot.Comment: 9 pages and 10 figures, new version, accepted in Physical Review
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