1,410 research outputs found

    Connection between the elastic GEp/GMp and P to Delta form factors

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    It is suggested that the falloff in Qsq of the P to Delta magnetic form factor GM* is related to the recently observed falloff of the elastic electric form factor GEp/GMp. Calculation is carried out in the framework of a GPD mechanism

    Mean parity of single quantum excitation of some optical fields in thermal environments

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    The mean parity (the Wigner function at the origin) of excited binomial states, excited coherent states and excited thermal states in thermal channel is investigated in details. It is found that the single-photon excited binomial state and the single-photon excited coherent state exhibit certain similarity in the aspect of their mean parity in the thermal channel. We show the negative mean parity can be regarded as an indicator of nonclassicality of single-photon excitation of optical fields with a little coherence, especially for the single-photon excited thermal states.Comment: 4 pages, 4 figures, RevTex4; PACS numbers: 42.50.Dv, 03.65.Yz, 05.40.Ca; Three typo errors have been correcte

    Linear amplification and quantum cloning for non-Gaussian continuous variables

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    We investigate phase-insensitive linear amplification at the quantum limit for single- and two-mode states and show that there exists a broad class of non-Gaussian states whose nonclassicality survives even at an arbitrarily large gain. We identify the corresponding observable nonclassical effects and find that they include, remarkably, two-mode entanglement. The implications of our results for quantum cloning outside the Gaussian regime are also addressed.Comment: published version with reference updat

    Comparison of Efficacy and Safety of Transcatheter Aortic Valve Implantation in Patients With Bicuspid Versus Tricuspid Aortic Valves

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    Bicuspid aortic valve (BAV) stenosis has been considered a contraindication to transcatheter aortic valve implantation (TAVI). The aim of this study is to compare the efficacy and safety of TAVI in patients with BAV with those with tricuspid aortic valve (TAV) using balloon-expandable and self-expanding transcatheter heart valves. This retrospective study included 823 consecutive patients with severe, symptomatic aortic valve stenosis undergoing TAVI in 2 institutions, Baylor Heart and Vascular Hospital (Dallas, TX) and The Heart Hospital Baylor Plano (Plano, TX), from January 2012 to February 2016. Efficacy was evaluated by postprocedural valve function as mean gradient, peak velocity, effective orifice area, and ≥moderate paravalvular leak. Safety end points included all-cause 30-day and 1-year mortality, immediate postprocedural mortality and 30-day cardiovascular mortality, procedural success, pacemaker implantation, and procedural complications. Of the 823 included patients, 735 had TAV and 77 had BAV. Baseline characteristics were similar between the 2 groups. Procedural success was high in both BAV and TAV (98.7% vs 99.1%, p = ns). There were no significant differences between groups in valve hemodynamics after TAVI, pacemaker implantation rate, or procedural complications. There were no differences regarding immediate postprocedural mortality (BAV vs TAV, 1.1% vs 0.8%, p = ns), nor 30-day cardiovascular mortality (3.4% vs 2.3%, p = ns). All-cause mortality at 30 days (3.4% vs 3.1%, p = ns) and 1-year (8.5% vs 10.5%) were similar. Patients with BAV showed similar procedural and clinical outcomes to patients with TAV. Therefore, TAVI appears to be a safe and effective procedure for patients with BAVs as well as those with TAVs

    Hermite Coherent States for Quadratic Refractive Index Optical Media

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    Producción CientíficaLadder and shift operators are determined for the set of Hermite–Gaussian modes associated with an optical medium with quadratic refractive index profile. These operators allow to establish irreducible representations of the su(1, 1) and su(2) algebras. Glauber coherent states, as well as su(1, 1) and su(2) generalized coherent states, were constructed as solutions of differential equations admitting separation of variables. The dynamics of these coherent states along the optical axis is also evaluated.MINECO grant MTM2014-57129-C2-1-P and Junta de Castilla y Leon grant VA057U16

    Approach to Perturbative Results in the N-Delta Transition

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    We show that constraints from perturbative QCD calculations play a role in the nucleon to Delta(1232) electromagnetic transition even at moderate momentum transfer scales. The pQCD constraints, tied to real photoproduction data and unseparated resonance response functions, lead to explicit forms for the helicity amplitudes wherein the E2/M1 ratio remains small at moderately large momentum transfer.Comment: 4 pages, 2 figures, ReVTe

    One-step generation of high-quality squeezed and EPR states in cavity QED

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    We show how to generate bilinear (quadratic) Hamiltonians in cavity quantum electrodynamics (QED) through the interaction of a single driven three-level atom with two (one) cavity modes. With this scheme it is possible to generate one-mode mesoscopic squeezed superpositions, two-mode entanglements, and two-mode squeezed vacuum states (such the original EPR state), without the need for Ramsey zones and external parametric amplification. The degree of squeezing achieved is up to 99% with currently feasible experimental parameters and the errors due to dissipative mechanisms become practically negligible

    Nonlocal properties of entangled two-photon generalized binomial states in two separate cavities

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    We consider entangled two-photon generalized binomial states of the electromagnetic field in two separate cavities. The nonlocal properties of this entangled field state are analyzed by studying the electric field correlations between the two cavities. A Bell's inequality violation is obtained using an appropriate dichotomic cavity operator, that is in principle measurable.Comment: 5 pages, 1 figur

    Statistics of Raman-Active Excitations via Masurement of Stokes-Anti-Stokes Correlations

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    A general fundamental relation connecting the correlation of Stokes and anti-Stokes modes to the quantum statistical behavior of vibration and pump modes in Raman-active materials is derived. We show that under certain conditions this relation can be used to determine the equilibrium number variance of phonons.Time and temperature ranges for which such conditions can be satisfied are studied and found to be available in todays' experimental standards. Furthermore, we examine the results in the presence of multi-mode pump as well as for the coupling of pump to the many vibration modes and discuss their validity in these cases.Comment: 12 pages, 1 figure, accepted for publication in Phys.Rev.
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