Cover illustration
The Relativistic Heavy-Ion Collider (RHIC) at Brookhaven National Laboratory was the first one that consisted of two independent rings. It was designed to operate at high luminosity over a wide range of beam energies and with particle species ranging from polarized proton to heavy ions. From central gold－gold collisions at the top center-of-mass energy of 200 GeV per nucleon－nucleon pair, thousands of particles were produced (see cover figure). With several years of data taki [Detail] ...
In this article, we review our recent theoretical works on producing ultracold molecules from ultracold bosonic atoms via magnetically tunable Feshbach resonances. Our analysis relies on a two-channel quantum microscopic model that accounts for many-body effects in the association process. We show that the picture of two-body molecular production depicted by the Landau–Zener model is signifi-cantly altered due to many-body effects. We derive an analytic expression for molecular conversion efficiency for the nonadiabatic linearly swept Feshbach resonance, that explains the discrepancy between the prediction of the Landau–Zener formula and the experimental data. With including the thermal dephasing effects in the oscillating magnetic field modulation Feshbach resoance, we reproduce the Lorentzian resonance lineshape and explain the maximum conversion efficiency observed in experiment.
Transferring a quantum state between a photon and a quantum memory is the key point for realizing a long-distance quantum communication, and is also a basic ingredient of linear optical quantum computation. In an atomic-based network, the efficient coupling between a photon and an atomic system is a prerequisite for realizing the transfer of information between them, which requires that the photon should have a comparable bandwidth with the natural bandwidth of an atom. Therefore, generating a narrow-band photon has become a very important topic in the quantum information field. One simple and efficient way is cavity-enhanced spontaneously parametric down-conversion. In this paper, we will review and introduce a series of experiments done in our group for realizing this goal. We believe these works are very useful for the research in this direction.
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, these two modes become one broad dispersionless mode that disappears just above the Fe ordering temperature !["Graphic"]("..\images\22\23\f1\79\hcm0000143793.html.graphics/HML40086.png.gif")
. For superconducting CeFeAsO0.84F0.16, where Fe static AF order is suppressed, we find a weakly dispersive mode center at 0.4 meV that may arise from short-range Ce–Ce exchange interactions. Using a Heisenberg model, we simulate powder-averaged Ce spin wave excitations. Our results show that we need both Ce spin wave and crystal electric field excitations to account for the whole spectra of low-energy spin excitations.
Perovskite oxides and heterojunctions have attracted much attention due to their multifunctional properties of electricity and optics and magnetic as well as the very good chemical and thermal stability. In this brief review, we describe the novel progress of researches in the optical characteristic, including ultrafast photoelectric effects of picosecond order in perovskite oxide single crystals, thin-films and heterojunctions, high-sensitive photovoltages, the enhanced transient lateral photovoltages in perovskite oxide thin-films and heterojunctions, and the high-sensitive ultraviolet (UV) photodetectors based on perovskite oxides. The recent advances present in this paper not only could stimulate theoretical studies on the mechanism but also would open up the possibilities in the developments of optoelectronic devices based on perovskite oxides and heterojunctions.
We study a one-dimensional Sine–Gordon lattice of anharmonic oscillators with cubic and quartic nearest-neighbor interactions, in which discrete breathers can be explicitly constructed by an exact separation of their time and space dependence. DBs can stably exist in the one-dimensional Sine–Gordon lattice no matter whether the nonlinear interaction is cubic or quartic. When a parametric driving term is introduced in the factor multiplying the harmonic part of the on-site potential of the system, we can obtain the stable quasiperiodic discrete breathers and chaotic discrete breathers by changing the amplitude of the driver.
The results from data taken during the last several years at the Relativistic Heavy-Ion Collider (RHIC) will be reviewed in the paper. Several selected topics that further our understanding of constituent quark scaling, jet quenching and color screening effect of heavy quarkonia in the hot dense medium will be presented. Detector upgrades will further probe the properties of Quark Gluon Plasma. Future measurements with upgraded detectors will be presented. The discovery perspectives from future measurements will also be discussed.
Based on our previous study of the QCD inspired eikonalized model for describing vector meson photoproduction,