7,811 research outputs found

    Squeezed States for General Systems

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    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

    Functional Forms for the Squeeze and the Time-Displacement Operators

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    Using Baker-Campbell-Hausdorff relations, the squeeze and harmonic-oscillator time-displacement operators are given in the form exp[δI]exp[α(x2)]exp[β(x)]exp[γ()2]\exp[\delta I] \exp[\alpha (x^2)]\exp[\beta(x\partial)] \exp[\gamma (\partial)^2], where α\alpha, β\beta, γ\gamma, and δ\delta are explicitly determined. Applications are discussed.Comment: 10 pages, LaTe

    General Approach to Functional Forms for the Exponential Quadratic Operators in Coordinate-Momentum Space

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    In a recent paper [Nieto M M 1996 Quantum and Semiclassical Optics, 8 1061; quant-ph/9605032], the one dimensional squeezed and harmonic oscillator time-displacement operators were reordered in coordinate-momentum space. In this paper, we give a general approach for reordering multi-dimensional exponential quadratic operator(EQO) in coordinate-momentum space. An explicit computational formula is provided and applied to the single mode and double-mode EQO through the squeezed operator and the time displacement operator of the harmonic oscillator.Comment: To appear in J. Phys. A: Mathematics and Genera

    Rydberg Wave Packets are Squeezed States

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    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

    Search for a Solution of the Pioneer Anomaly

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    In 1972 and 1973 the Pioneer 10 and 11 missions were launched. They were the first to explore the outer solar system and achieved stunning breakthroughs in deep-space exploration. But beginning in about 1980 an unmodeled force of \sim 8 \times 10^{-8} cm/s^2, directed approximately towards the Sun, appeared in the tracking data. It later was unambiguously verified as being in the data and not an artifact. The cause remains unknown (although radiant heat remains a likely origin). With time more and more effort has gone into understanding this anomaly (and also possibly related effects). We review the situation and describe ongoing programs to resolve the issue.Comment: 24 pages 8 figure

    Indication, from Pioneer 10/11, Galileo, and Ulysses Data, of an Apparent Anomalous, Weak, Long-Range Acceleration

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    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 8.5×108\sim 8.5\times 10^{-8} cm/s2^2, 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

    Exact, E=0, Solutions for General Power-Law Potentials. I. Classical Orbits

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    For zero energy, E=0E=0, we derive exact, classical solutions for {\em all} power-law potentials, V(r)=γ/rνV(r)=-\gamma/r^\nu, with γ>0\gamma>0 and <ν<-\infty <\nu<\infty. When the angular momentum is non-zero, these solutions lead to the orbits (˚t)=[cosμ(th(t)th0(t))]1/μ\r(t)= [\cos \mu (\th(t)-\th_0(t))]^{1/\mu}, for all μν/210\mu \equiv \nu/2-1 \ne 0. When ν>2\nu>2, the orbits are bound and go through the origin. This leads to discrete discontinuities in the functional dependence of th(t)\th(t) and th0(t)\th_0(t), as functions of tt, as the orbits pass through the origin. We describe a procedure to connect different analytic solutions for successive orbits at the origin. We calculate the periods and precessions of these bound orbits, and graph a number of specific examples. Also, we explain why they all must violate the virial theorem. The unbound orbits are also discussed in detail. This includes the unusual orbits which have finite travel times to infinity and also the special ν=2\nu = 2 case.Comment: LaTeX, 27 pages with 12 figures available from the authors or can be generated from Mathematica instructions at end of the fil

    Globular Cluster Systems of Early-Type Galaxies

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    Properties of 53 globular cluster systems are investigated. Strong correlations are found between parent galaxy luminosity and both the slope of the radial density profile for clusters and the width of the cluster color (metallicity) distribution. These correlations are in the sense that the most luminous early-type galaxies are embedded in cluster systems that have the shallowest radial gradients and exhibit the broadest color distributions. The data suggest a scenario in which luminous early-type galaxies have a more complex evolutionary history than fainter ones. A problem with the interpretation of the present data is that it is difficult (or impossible) to disentangle the strongly correlated effects of high parent galaxy luminosity, presence of a core or boxy isophotes, and shallow radial cluster density gradients.Comment: Contains complete Table 1 which had been truncated. To appear in the Astrophysical Journal. Also available at http://www.hia.nrc.ca/eprints.htm

    Time Delay Predictions in a Modified Gravity Theory

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    The time delay effect for planets and spacecraft is obtained from a fully relativistic modified gravity theory including a fifth force skew symmetric field by fitting to the Pioneer 10/11 anomalous acceleration data. A possible detection of the predicted time delay corrections to general relativity for the outer planets and future spacecraft missions is considered. The time delay correction to GR predicted by the modified gravity is consistent with the observational limit of the Doppler tracking measurement reported by the Cassini spacecraft on its way to Saturn, and the correction increases to a value that could be measured for a spacecraft approaching Neptune and Pluto.Comment: 5 pages, LaTex file, no figures. Corrections to Table

    Topiramate in the treatment of severe myoclonic epilepsy in infancy

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    AbstractThe aim of this study was to assess the effectiveness of topiramate (TPM) as an add-on regimen in reducing seizure rate in a population sample of patients diagnosed with severe myoclonic epilepsy in infancy (SME). Eighteen patients were evaluated. The mean observation time was 10.5 months (range, 6–18 months). Seizure frequency and type were recorded. Topiramate was administered as an add-on regimen at a starting dose of 1 mg kg−1and titrated to a maximum of 6–8 mg per kg per day. Different escalation rates were used, mainly weekly or fortnightly increments of dose. Three patients (16.6%) became seizure free, and 10 (55.6%) had a >50% reduction in seizure frequency: six of them (22.2%) achieved a reduction greater than 75%. Side-effects were observed in nine patients , eight with a weekly titration schedule and one with a fortnightly schedule. TPM is effective as adjunctive therapy for SME. Side-effects were mild and transient, generally related to rapid dosage titration
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