283 research outputs found
The quest for three-color entanglement: experimental investigation of new multipartite quantum correlations
We experimentally investigate quadrature correlations between pump, signal,
and idler fields in an above-threshold optical parametric oscillator. We
observe new quantum correlations among the pump and signal or idler beams, as
well as among the pump and a combined quadrature of signal and idler beams. A
further investigation of unforeseen classical noise observed in this system is
presented, which hinders the observation of the recently predicted tripartite
entanglement. In spite of this noise, current results approach the limit
required to demonstrate three-color entanglement.Comment: 10 pages, 5 figures, submitted to Opt. Expres
Classical Analog of Electromagnetically Induced Transparency
We present a classical analog for Electromagnetically Induced Transparency
(EIT). In a system of just two coupled harmonic oscillators subject to a
harmonic driving force we can reproduce the phenomenology observed in EIT. We
describe a simple experiment performed with two linearly coupled RLC circuits
which can be taught in an undergraduate laboratory class.Comment: 6 pages, two-column, 6 figures, submitted to the Am. J. Phy
Direct Production of Tripartite Pump-Signal-Idler Entanglement in the Above-Threshold Optical Parametric Oscillator
We calculate the quantum correlations existing among the three output fields
(pump, signal, and idler) of a triply resonant non-degenerate Optical
Parametric Oscillator operating above threshold. By applying the standard
criteria [P. van Loock and A. Furusawa, Phys. Rev. A 67, 052315 (2003)], we
show that strong tripartite continuous-variable entanglement is present in this
well-known and simple system. Furthermore, since the entanglement is generated
directly from a nonlinear process, the three entangled fields can have very
different frequencies, opening the way for multicolored quantum information
networks.Comment: 4 pages, 3 figure
Theory of Optical Tweezers
We derive a partial-wave (Mie) expansion of the axial force exerted on a
transparent sphere by a laser beam focused through a high numerical aperture
objective. The results hold throughout the range of interest for practical
applications. The ray optics limit is shown to follow from the Mie expansion by
size averaging. Numerical plots show large deviations from ray optics near the
focal region and oscillatory behavior (explained in terms of a simple
interferometer picture) of the force as a function of the size parameter.
Available experimental data favor the present model over previous ones.Comment: 4 pages, 3 figure
Serfati solutions to the 2D Euler equations on exterior domains
We prove existence and uniqueness of a weak solution to the incompressible 2D
Euler equations in the exterior of a bounded smooth obstacle when the initial
data is a bounded divergence-free velocity field having bounded scalar curl.
This work completes and extends the ideas outlined by P. Serfati for the same
problem in the whole-plane case. With non-decaying vorticity, the Biot-Savart
integral does not converge, and thus velocity cannot be reconstructed from
vorticity in a straightforward way. The key to circumventing this difficulty is
the use of the Serfati identity, which is based on the Biot-Savart integral,
but holds in more general settings.Comment: 50 page
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