J/ψ+jetJ/\psi + jet diffractive production in the direct photon process at HERA

We present a study of $J/\psi + jet$ diffractive production in the direct photon process at HERA based on the factorization theorem for lepton-induced hard diffractive scattering and the factorization formalism of the nonrelativistic QCD (NRQCD) for quarkonia production. Using the diffractive gluon distribution function extracted from HERA data on diffractive deep inelastic scattering and diffractive dijet photon production, we show that this process can be studied at HERA with present integrated luminosity, and can give valuable insights in the color-octet mechanism for heavy quarkonia production.Comment: Revtex, 21 pages, 7 EPS figure

Transverse Mode Revival of a Light-Compensated Quantum Memory

A long-lived quantum memory was developed based on light-compensated cold $^{87}$Rb atoms in a dipole trap. The lifetime of the quantum memory was improved by 40 folds, from 0.67 ms to 28 ms with the help of a compensation laser beam. Oscillations of the memory efficiency due to the transverse mode breathing of the singly-excited spin wave have been clearly observed and clarified with a Monte-Carlo simulation procedure. With detailed analysis of the decoherence processes of the spin wave in cold atomic ensembles, this experiment provides a benchmark for the further development of high-quality quantum memories.Comment: 4 pages, 4 figure

Quantum interface between frequency-uncorrelated down-converted entanglement and atomic-ensemble quantum memory

Photonic entanglement source and quantum memory are two basic building blocks of linear-optical quantum computation and long-distance quantum communication. In the past decades, intensive researches have been carried out, and remarkable progress, particularly based on the spontaneous parametric down-converted (SPDC) entanglement source and atomic ensembles, has been achieved. Currently, an important task towards scalable quantum information processing (QIP) is to efficiently write and read entanglement generated from a SPDC source into and out of an atomic quantum memory. Here we report the first experimental realization of a quantum interface by building a 5 MHz frequency-uncorrelated SPDC source and reversibly mapping the generated entangled photons into and out of a remote optically thick cold atomic memory using electromagnetically induced transparency. The frequency correlation between the entangled photons is almost fully eliminated with a suitable pump pulse. The storage of a triggered single photon with arbitrary polarization is shown to reach an average fidelity of 92% for 200 ns storage time. Moreover, polarization-entangled photon pairs are prepared, and one of photons is stored in the atomic memory while the other keeps flying. The CHSH Bell's inequality is measured and violation is clearly observed for storage time up to 1 microsecond. This demonstrates the entanglement is stored and survives during the storage. Our work establishes a crucial element to implement scalable all-optical QIP, and thus presents a substantial progress in quantum information science.Comment: 28 pages, 4 figures, 1 tabl

Guidezilla extension catheter for percutaneous interventional therapy of complex lesions via a transradial approach: Case series from a single-center experience

   Background: Guide catheter extension systems have become one of the most powerful tools for address­ing complex lesions during percutaneous coronary intervention (PCI), but data on a new-generation rapid exchange extension catheter — the Guidezilla catheter — are limited. Summarized herein reports on experience using the Guidezilla catheter for complex coronary lesions via a transradial approach at the documented institution an evaluation of its safety and efficacy. Methods: A total of 25 patients (19 males and 6 females) who underwent PCI via the radial approach with the Guidezilla catheter for adequate back-up support and to facilitate equipment delivery were enrolled. The clinical, angiographic and procedural data of all 26 procedures in 25 patients (1 patient underwent two PCI procedures on different lesions) were collected to evaluate the safety and efficacy of this novel equipment. Results: The mean age of the enrolled patients was 67.7 ± 8.41 years old. The mean depth of intuba­tion was 27.90 ± 12.23 mm. Stent implantation was successful in 23 out of 26 procedures (88.5%) and failed in 3 cases: 1 case of tortuosity and severe angulation in a chronic total occlusion lesion; 1 case of an existing type B dissection (NHLBI classification system for coronary artery dissection types); and 1 case in which a stent was stripped off its balloon. None of the patients experienced coronary dissection, perforation, air embolism, pressure dampening or other major complications during the procedure. Conclusions: The Guidezilla extension catheter is an effective and safe tool that provides improved back-up support and increases the success rate of PCI for complex coronary lesion by radial access