142,662 research outputs found

    Heavy Quarkonium

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    I review heavy quarkonium physics in view of recent experimental results. In particular, I discuss new results on spin singlet states, photon and hadronic transitions, D-states and discovery of yet unexplained narrow X(3872) state.Comment: 15 pages, 16 figures. 2nd version: minor changes in references and text. Invited talk presented at the 21st International Symposium On Lepton And Photon Interactions At High Energies (LP03) 11-16 August 2003, Batavia, Illinoi

    Automated weighing by sequential inference in dynamic environments

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    We demonstrate sequential mass inference of a suspended bag of milk powder from simulated measurements of the vertical force component at the pivot while the bag is being filled. We compare the predictions of various sequential inference methods both with and without a physics model to capture the system dynamics. We find that non-augmented and augmented-state unscented Kalman filters (UKFs) in conjunction with a physics model of a pendulum of varying mass and length provide rapid and accurate predictions of the milk powder mass as a function of time. The UKFs outperform the other method tested - a particle filter. Moreover, inference methods which incorporate a physics model outperform equivalent algorithms which do not.Comment: 5 pages, 7 figures. Copyright IEEE (2015

    Bound States in n Dimensions (Especially n = 1 and n = 2)

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    We stress that in contradiction with what happens in space dimensions n‚Č•3n \geq 3, there is no strict bound on the number of bound states with the same structure as the semi-classical estimate for large coupling constant and give, in two dimensions, examples of weak potentials with one or infinitely many bound states. We derive bounds for one and two dimensions which have the "right" coupling constant behaviour for large coupling.Comment: Talk given by A. Martin at Les Houches, October 2001, to appear in "Few-Body Problems

    The period-luminosity and period-radius relations of Type II and anomalous Cepheids

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    Method: In an accompanying paper (arXiv: 1705.00886) we determined luminosity and effective temperature for the 335 T2Cs and ACs in the LMC and SMC discovered in the OGLE-III survey, by constructing the spectral energy distribution (SED) and fitting this with model atmospheres and a dust radiative transfer model (in the case of dust excess). Building on these results we study the PL and PR relations. Using existing pulsation models for RR Lyrae and classical Cepheids we derive the period-luminosity-mass-temperature-metallicity relations, and then estimate the pulsation mass. Results: The PL relation for the T2Cs does not appear to depend on metallicity, and, excluding the dusty RV Tau stars, is Mbol=+0.12‚ąí1.78log‚Ā°PM_{\rm bol}= +0.12 -1.78 \log P (for P<50P < 50 days). Relations for fundamental and first overtone LMC ACs are also presented. The PR relation for T2C also shows little or no dependence on metallicity or period. Our preferred relation combines SMC and LMC stars and all T2C subclasses, and is log‚Ā°R=0.846+0.521log‚Ā°P\log R = 0.846 + 0.521 \log P. Relations for fundamental and first overtone LMC ACs are also presented. The pulsation masses from the RR Lyrae and classical Cepheid pulsation models agree well for the short period T2Cs, the BL Her subtype, and ACs, and are consistent with estimates in the literature, i.e. MBLH‚ąľ0.49M_{\rm BLH} \sim 0.49 \msol\ and MAC¬†‚ąľ1.3M_{\rm AC} ~\sim 1.3 \msol, respectively. The masses of the W Vir appear similar to the BL Her. The situation for the pWVir and RV Tau stars is less clear. For many RV Tau the masses are in conflict with the standard picture of (single-star) post-AGB evolution, the masses being either too large (‚Č≥\gtrsim 1 \msol) or too small (‚Č≤\lesssim 0.4 \msol).Comment: A&A accepte

    Phonon Squeezing in a Superconducting Molecular Transistor

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    Josephson transport through a single molecule or carbon nanotube is considered in the presence of a local vibrational mode coupled to the electronic charge. The ground-state solution is obtained exactly in the limit of a large superconducting gap, and is extended to the general case by variational analysis. Coherent charge fluctuations are entangled with non-classical phonon states. The Josephson current induces squeezing of the phonon mode, which is controlled by the superconducting phase difference and by the junction asymmetry. Optical probes of non-classical phonon states are briefly discussed
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