8,429 research outputs found
Simulations of Sisyphus cooling including multiple excited states
We extend the theory for laser cooling in a near-resonant optical lattice to
include multiple excited hyperfine states. Simulations are performed treating
the external degrees of freedom of the atom, i.e., position and momentum,
classically, while the internal atomic states are treated quantum mechanically,
allowing for arbitrary superpositions. Whereas theoretical treatments including
only a single excited hyperfine state predict that the temperature should be a
function of lattice depth only, except close to resonance, experiments have
shown that the minimum temperature achieved depends also on the detuning from
resonance of the lattice light. Our results resolve this discrepancy.Comment: 7 pages, 6 figure
The feasibility study for electronic imaging system with the photoheliograph
The development of the electronic subsystems used for the photoheliograph and its application for a high resolution study of the sun are discussed. Basic considerations are as follows: (1) determination of characteristics of solar activity within the spectral response of the photoheliograph, (2) determination of the space vehicles capable of carrying the photoheliograph, (3) analysis of the capability of the ground based data gathering network to assimilate the generated information, and (4) the characteristics of the photoheliograph and the associated spectral filters
Poisson multi-Bernoulli mixture trackers: continuity through random finite sets of trajectories
The Poisson multi-Bernoulli mixture (PMBM) is an unlabelled multi-target
distribution for which the prediction and update are closed. It has a Poisson
birth process, and new Bernoulli components are generated on each new
measurement as a part of the Bayesian measurement update. The PMBM filter is
similar to the multiple hypothesis tracker (MHT), but seemingly does not
provide explicit continuity between time steps. This paper considers a recently
developed formulation of the multi-target tracking problem as a random finite
set (RFS) of trajectories, and derives two trajectory RFS filters, called PMBM
trackers. The PMBM trackers efficiently estimate the set of trajectories, and
share hypothesis structure with the PMBM filter. By showing that the prediction
and update in the PMBM filter can be viewed as an efficient method for
calculating the time marginals of the RFS of trajectories, continuity in the
same sense as MHT is established for the PMBM filter
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