7,642 research outputs found
A dynamic economy with shares, fiat, bank and accounting money
monetary models;monetary economics
Quantum correlations of an atomic ensemble via a classical bath
Somewhat surprisingly, quantum features can be extracted from a classical
bath. For this, we discuss a sample of three-level atoms in ladder
configuration interacting only via the surrounding bath, and show that the
fluorescence light emitted by this system exhibits non-classical properties.
Typical realizations for such an environment are thermal baths for microwave
transition frequencies, or incoherent broadband fields for optical transitions.
In a small sample of atoms, the emitted light can be switched from sub- to
super-poissonian and from anti-bunching to super-bunching controlled by the
mean number of atoms in the sample. Larger samples allow to generate
super-bunched light over a wide range of bath parameters and thus fluorescence
light intensities. We also identify parameter ranges where the fields emitted
on the two transitions are correlated or anti-correlated, such that the
Cauchy-Schwarz inequality is violated. As in a moderately strong baths this
violation occurs also for larger numbers of atoms, such samples exhibit
mesoscopic quantum effects.Comment: 4 page
Inference Optimization using Relational Algebra
Exact inference procedures in Bayesian networks can be expressed using relational algebra; this provides a common ground for optimizations from the AI and database communities. Specifically, the ability to accomodate sparse representations of probability distributions opens up the way to optimize for their cardinality instead of the dimensionality; we apply this in a sensor data model.\u
Localization of atomic ensembles via superfluorescence
The sub-wavelength localization of an ensemble of atoms concentrated to a
small volume in space is investigated. The localization relies on the
interaction of the ensemble with a standing wave laser field. The light
scattered in the interaction of standing wave field and atom ensemble depends
on the position of the ensemble relative to the standing wave nodes. This
relation can be described by a fluorescence intensity profile, which depends on
the standing wave field parameters, the ensemble properties, and which is
modified due to collective effects in the ensemble of nearby particles. We
demonstrate that the intensity profile can be tailored to suit different
localization setups. Finally, we apply these results to two localization
schemes. First, we show how to localize an ensemble fixed at a certain position
in the standing wave field. Second, we discuss localization of an ensemble
passing through the standing wave field.Comment: 7 pages, 6 figure
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