114 research outputs found
Compressive ghost imaging
We describe an advanced image reconstruction algorithm for pseudothermal
ghost imaging, reducing the number of measurements required for image recovery
by an order of magnitude. The algorithm is based on compressed sensing, a
technique that enables the reconstruction of an N-pixel image from much less
than N measurements. We demonstrate the algorithm using experimental data from
a pseudothermal ghost-imaging setup. The algorithm can be applied to data taken
from past pseudothermal ghost-imaging experiments, improving the
reconstruction's quality.Comment: Comments are welcom
Quantum Correlations in Two-Particle Anderson Localization
We predict the quantum correlations between non-interacting particles
evolving simultaneously in a disordered medium. While the particle density
follows the single-particle dynamics and exhibits Anderson localization, the
two-particle correlation develops unique features that depend on the quantum
statistics of the particles and their initial separation. On short time scales,
the localization of one particle becomes dependent on whether the other
particle is localized or not. On long time scales, the localized particles show
oscillatory correlations within the localization length. These effects can be
observed in Anderson localization of non-classical light and ultra-cold atoms.Comment: 4 pages, 4 figures, comments welcom
Classical Bound for Mach-Zehnder Super-Resolution
The employment of path entangled multiphoton states enables measurement of
phase with enhanced precision. It is common practice to demonstrate the unique
properties of such quantum states by measuring super-resolving oscillations in
the coincidence rate of a Mach-Zehnder interferometer. Similar oscillations,
however, have also been demonstrated in various configurations using classical
light only; making it unclear what, if any, are the classical limits of this
phenomenon. Here we derive a classical bound for the visibility of
super-resolving oscillations in a Mach-Zehnder. This provides an easy to apply,
fundamental test of non-classicality. We apply this test to experimental
multiphoton coincidence measurements obtained using photon number resolving
detectors. Mach-Zehnder super-resolution is found to be a highly distinctive
quantum effect.Comment: 4 pages, 4 figure, Comments welcom
Two-photon path-entangled states in multi-mode waveguides
We experimentally show that two-photon path-entangled states can be
coherently manipulated by multi-mode interference in multi-mode waveguides. By
measuring the output two-photon spatial correlation function versus the phase
of the input state, we show that multi-mode waveguides perform as nearly-ideal
multi-port beam splitters at the quantum level, creating a large variety of
entangled and separable multi-path two-photon states.Comment: 4 pages, 4 figure
Bloch oscillations of Path-Entangled Photons
We show that when photons in N-particle path entangled |N,0> + |0,N> state
undergo Bloch oscillations, they exhibit a periodic transition between
spatially bunched and antibunched states. The transition occurs even when the
photons are well separated in space. We study the scaling of the
bunching-antibunching period, and show it is proportional to 1/N.Comment: An error in figure 1b of the original manuscript was corrected, and
the period was redefine
Spectral Polarization and Spectral Phase Control of Time and Energy Entangled Photons
We demonstrate a scheme to spectrally manipulate a collinear, continuous
stream of time and energy entangled photons to generate beamlike,
bandwidth-limited fuxes of polarization-entangled photons with
nearly-degenerate wavelengths. Utilizing an ultrashort-pulse shaper to control
the spectral phase and polarization of the photon pairs, we tailor the shape of
the Hong-Ou-Mandel interference pattern, demonstrating the rules that govern
the dependence of this interference pattern on the spectral phases of the
photons. We then use the pulse shaper to generate all four polarization Bell
states. The singlet state generated by this scheme forms a very robust
decoherence-free subspace, extremely suitable for long distance fiber-optics
based quantum communication.Comment: 5 pages, 3 figure
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