68 research outputs found
Bright tripartite entanglement in triply concurrent parametric oscillation
We show that a novel optical parametric oscillator, based on concurrent
nonlinearities, can produce, above threshold, bright output beams
of macroscopic intensities which exhibit strong tripartite continuous-variable
entanglement. We also show that there are {\em two} ways that the system can
exhibit a new three-mode form of the Einstein-Podolsky-Rosen paradox, and
calculate the extra-cavity fluctuation spectra that may be measured to verify
our predictions.Comment: title change, expanded intro and discussion of experimental aspects,
1 new figure. Conclusions unaltere
Double-lambda microscopic model for entangled light generation by four-wave-mixing
Motivated by recent experiments, we study four-wave-mixing in an atomic
double-{\Lambda} system driven by a far-detuned pump. Using the
Heisenberg-Langevin formalism, and based on the microscopic properties of the
medium, we calculate the classical and quantum properties of seed and conju-
gate beams beyond the linear amplifier approximation. A continuous variable
approach gives us access to relative-intensity noise spectra that can be
directly compared to experiments. Restricting ourselves to the cold-atom
regime, we predict the generation of quantum-correlated beams with a
relative-intensity noise spectrum well below the standard quantum limit (down
to -6 dB). Moreover entanglement between seed and conjugate beams measured by
an inseparability down to 0.25 is expected. This work opens the way to the
generation of entangled beams by four-wave mixing in a cold atomic sample.Comment: 11 pages, 6 figures, submitted to PR
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