37,265 research outputs found
Study of Counting Characteristics of Porous Radiation Detectors
This paper presents the development of a new technology of registration of
ionizing radiation and a new type of detectors - single-cathode multiwire
porous detector with neither a gaseous nor semiconductor, but a porous
dielectric substance, e.g., CsI, being used as working medium. It is shown that
the performance of the multiwire porous detector is stable, ensuring highly
efficient detection of both heavily ionizing particles and soft X-rays with a
spatial resolution better than . The continuous stable performance
opens up new perspectives for using porous detectors in research as well as
medicine. The obtained data are basic for the development of the theory of the
phenomenon of electrons' drift and multiplication in porous dielectrics under
the action of a strong external electric field.Comment: 43
Experiment on Interaction-Free Measurement in Neutron Interferometry
A neutron interferometric test of interaction-free detection of the presence
of an absorbing object in one arm of a neutron interferometer has been
performed. Despite deviations from the ideal performance characteristics of a
Mach-Zehnder interferometer it could be shown that information is obtained
without interaction.Comment: 8 pages, 4 postscript figures; submitted to Phys.Lett.A; Figures
contained only in replaced versio
Delayed Choice, Complementarity, Entanglement and Measurement
It is well known that Wheeler proposed several delayed choice experiments in
order to show the impossibility to speak of the way a quantum system behaves
before being detected. In a double-slit experiment, when do photons decide to
travel by one way or by two ways? Delayed choice experiments seem to indicate
that, strangely, it is possible to change the decision of the photons until the
very last moment before they are detected. This led Wheeler to his famous
sentence: No elementary quantum phenomenon is a phenomenon until it is a
registered phenomenon, brought to a close by an irreversible act of
amplification. Nevertheless some authors wrote that backward in time effects
were needed to explain these results. I will show that in delayed choice
experiments involving only one particle, a simple explanation is possible
without invoking any backward in time effect. Delayed choice experiments
involving entangled particles such as the so called quantum eraser can also be
explained without invoking any backward in time effect but I will argue that
these experiments cannot be accounted for so simply because they rise the whole
problem of knowing what a measurement and a collapse are. A previously
presented interpretation, Convivial Solipsism, is a natural framework for
giving a simple explanation of these delayed choice experiments with entangled
particles. In this paper, I show how Convivial Solipsism helps clarifying the
puzzling questions raised by the collapse of the wave function of entangled
systems.Comment: 3 figure
Popper's Experiment: A Modern Perspective
Karl Popper had proposed an experiment to test the standard interpretation of
quantum mechanics. The proposal survived for many year in the midst of no clear
consensus on what results it would yield. The experiment was realized by Kim
and Shih in 1999, and the apparently surprising result led to lot of debate. We
review Popper's proposal and its realization in the light of current era when
entanglement has been well studied, both theoretically and experimentally. We
show that the "ghost-diffraction" experiment, carried out in a different
context, conclusively resolves the controversy surrounding Popper's experiment.Comment: Review article (11 pages, 2-column) published versio
Quantum detection of wormholes
We show how to use quantum metrology to detect a wormhole. A coherent state
of the electromagnetic field experiences a phase shift with a slight dependence
on the throat radius of a possible distant wormhole. We show that this tiny
correction is, in principle, detectable by homodyne measurements after long
propagation lengths for a wide range of throat radii and distances to the
wormhole, even if the detection takes place very far away from the throat,
where the spacetime is very close to a flat geometry. We use realistic
parameters from state-of-the-art long-baseline laser interferometry, both
Earth-based and space-borne. The scheme is, in principle, robust to optical
losses and initial mixedness.Comment: 5 pages, 4 figures. v2: minor changes, published versio
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