1,864 research outputs found
Two-mode squeezed vacuum and squeezed light in correlated interferometry
We study in detail a system of two interferometers aimed to the detection of
extremely faint phase-fluctuations. This system can represent a breakthrough
for detecting a faint correlated signal that would remain otherwise
undetectable even using the most sensitive individual interferometric devices,
that are limited by the shot noise. If the two interferometers experience
identical phase-fluctuations, like the ones introduced by the so called
"holographic noise", this signal should emerge if their output signals are
correlated, while the fluctuations due to shot noise and other independent
contributions will vanish. We show how the injecting quantum light in the free
ports of the interferometers can reduce the photon noise of the system beyond
the shot-noise, enhancing the resolution in the phase-correlation estimation.
We analyze both the use of two-mode squeezed vacuum or twin-beam state (TWB)
and of two independent squeezing states. Our results basically confirms the
benefit of using squeezed beams together with strong coherent beams in
interferometry, even in this correlated case. However, mainly we concentrate on
the possible use of TWB, discovering interesting and probably unexplored areas
of application of bipartite entanglement and in particular the possibility of
reaching in principle surprising uncertainty reduction
Toward third order ghost imaging with thermal light
Recently it has been suggested that an enhancement in the visibility of ghost
images obtained with thermal light can be achieved exploiting higher order
correlations [3]. This paper reports on the status of an higher order ghost
imaging experiment carried on at INRIM labs exploiting a pseudo-thermal source
and a CCD camera.Comment: To be published in Proceedings of Recent advances in Foundations of
Quantum Mechanics and Quantum Informatio
Experimental Quantum Imaging exploiting multi-mode spatial correlation of twin beams
Properties of quantum states have disclosed new and revolutionary
technologies, ranging from quantum information to quantum imaging. This last
field is addressed to overcome limits of classical imaging by exploiting
specific properties of quantum states of light. One of the most interesting
proposed scheme exploits spatial quantum correlations between twin beams for
realizing sub-shot-noise imaging of the weak absorbing objects, leading ideally
to a noise-free imaging. Here we discuss in detail the experimental realization
of this scheme, showing its capability to reach a larger signal to noise ratio
with respect to classical imaging methods and, therefore, its interest for
future practical applications
Revealing interference by continuous variable discordant states
In general, a pair of uncorrelated Gaussian states mixed in a beam splitter
produces a correlated state at the output. However, when the inputs are
identical Gaussian states the output state is equal to the input, and no
correlations appear, as the interference had not taken place. On the other
hand, since physical phenomena do have observable effects, and the beam
splitter is there, a question arises on how to reveal the interference between
the two beams. We prove theoretically and demonstrate experimentally that this
is possible if at least one of the two beams is prepared in a discordant, i.e.
Gaussian correlated, state with a third beam. We also apply the same technique
to reveal the erasure of polarization information. Our experiments involves
thermal states and the results show that Gaussian discordant states, even when
they show a positive Glauber P-function, may be useful to achieve specific
tasks.Comment: published versio
- …