8,354 research outputs found
Rydberg Wave Packets are Squeezed States
We point out that Rydberg wave packets (and similar ``coherent" molecular
packets) are, in general, squeezed states, rather than the more elementary
coherent states. This observation allows a more intuitive understanding of
their properties; e.g., their revivals.Comment: 7 pages of text plus one figure available in the literature, LA-UR
93-2804, to be published in Quantum Optics, LaTe
Heisenberg-type higher order symmetries of superintegrable systems separable in cartesian coordinates
Heisenberg-type higher order symmetries are studied for both classical and
quantum mechanical systems separable in cartesian coordinates. A few particular
cases of this type of superintegrable systems were already considered in the
literature, but here they are characterized in full generality together with
their integrability properties. Some of these systems are defined only in a
region of , and in general they do not include bounded solutions.
The quantum symmetries and potentials are shown to reduce to their
superintegrable classical analogs in the limit.Comment: 23 Pages, 3 figures, To appear in Nonlinearit
Superintegrability of the Fock-Darwin system
The Fock-Darwin system is analysed from the point of view of its symmetry
properties in the quantum and classical frameworks. The quantum Fock-Darwin
system is known to have two sets of ladder operators, a fact which guarantees
its solvability. We show that for rational values of the quotient of two
relevant frequencies, this system is superintegrable, the quantum symmetries
being responsible for the degeneracy of the energy levels. These symmetries are
of higher order and close a polynomial algebra. In the classical case, the
ladder operators are replaced by ladder functions and the symmetries by
constants of motion. We also prove that the rational classical system is
superintegrable and its trajectories are closed. The constants of motion are
also generators of symmetry transformations in the phase space that have been
integrated for some special cases. These transformations connect different
trajectories with the same energy. The coherent states of the quantum
superintegrable system are found and they reproduce the closed trajectories of
the classical one.Comment: 21 pages,16 figure
Magnetic noise around metallic microstructures
We compute the local spectrum of the magnetic field near a metallic
microstructure at finite temperature. Our main focus is on deviations from a
plane-layered geometry for which we review the main properties. Arbitrary
geometries are handled with the help of numerical calculations based on surface
integral equations. The magnetic noise shows a significant polarization
anisotropy above flat wires with finite lateral width, in stark contrast to an
infinitely wide wire. Within the limits of a two-dimensional setting, our
results provide accurate estimates for loss and dephasing rates in so-called
`atom chip traps' based on metallic wires. A simple approximation based on the
incoherent summation of local current elements gives qualitative agreement with
the numerics, but fails to describe current correlations among neighboring
objects.Comment: 10 pages, 9 figures, accepted for publication in J Appl Phys; figures
plotted for slightly smaller structur
Indication, from Pioneer 10/11, Galileo, and Ulysses Data, of an Apparent Anomalous, Weak, Long-Range Acceleration
Radio metric data from the Pioneer 10/11, Galileo, and Ulysses spacecraft
indicate an apparent anomalous, constant, acceleration acting on the spacecraft
with a magnitude cm/s, directed towards the Sun.
Two independent codes and physical strategies have been used to analyze the
data. A number of potential causes have been ruled out. We discuss future
kinematic tests and possible origins of the signal.Comment: Revtex, 4 pages and 1 figure. Minor changes for publicatio
Squeezed States for General Systems
We propose a ladder-operator method for obtaining the squeezed states of
general symmetry systems. It is a generalization of the annihilation-operator
technique for obtaining the coherent states of symmetry systems. We connect
this method with the minimum-uncertainty method for obtaining the squeezed and
coherent states of general potential systems, and comment on the distinctions
between these two methods and the displacement-operator method.Comment: 8 pages, LAUR-93-1721, LaTe
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