Crossed Beam Experiment on the Validity of Born-Oppenheimer Approximation in Cl(2P)+D2→DCl+D Reaction

The reaction of chlorine atom Cl(2P)(Cl(2P3/2)and Cl^*(2P1/2))with D2 was investigated at collision energy from 4.5 kcal/mol to 6.5 kcal/mol with a high-resolution crossed molecular beam apparatus using the technique of D-atom Rydberg tagging detection.The contribution from the spin-orbit excited reaction Cl^*(2P1/2)+D2,which is prohibited by Born-Oppenheimer(BO)approximation,was observed.Collision-energy dependence of differential cross sections(DCSs)near the backward scattering direction was measured.The BOforbidden reaction Cl^*+D2 was found to be dominant at lower collision energy.As collision energy increases,reactivity of BO-allowed reaction Cl+D2 increases much faster than that of BO-forbidden reaction and becomes dominant at higher collision energy.Our experiment indicates that the additional energy of spin-orbit excitation in Cl^*facilitates BO-forbidden reaction to pass through the barrier at lower collision energy,while BO approximation is still valid at collision energy near and above the reaction barrier.This tendency of reactivity of Cl/Cl^*+D2 is similar to the isotopic reaction of Cl/Cl^*+H2.

Electronic Absorption Spectroscopy of H2X （X=O, Te, Po）： Theoretical Treatment of Spin-Orbit Effects

The electronic spectroscopy of H2X （X=O, Te, Po） was investigated by means of spinorbit configuration interaction （EPCISO） and restricted active space state interaction （SORASSI）. The transition energies to the low-lying singlet and triplet states of H2O, in which the SO interaction is zero, compare rather well with the experimental data as well as to other theoretical values. The theoretical electronic absorption spectrum is characterized by three allowed transitions A^1B1 （2px（O）→σ^＊g/3s（O））, B^1A1（σg→σ^＊g/3s（O）） and A^1S2（σg→σ^＊u） calculated at 7.68, 9.94, and 11.72 eV, respectively. The theoretical absorption spectra of H2X （X=Te, Po） are shifted to the red with the A^1B1 （npx（X）→σ^＊g） states calculated at 5.06 eV （H2Te） and 4.40 eV （H2Po） and the A^1B2 （σg→σ^＊u） states calculated at 7.89 eV （H2Te） and 7.77 eV （H2Po）. The largest SO splitting amounts to 0.34 eV and is found for the lowest a^3A1 of H2Po. In H2Te the SO effects are still negligible with a maximum splitting of 0.04 eV for the lowest a^3B2. The two methods lead to comparable results but the EPCISO approach depends strongly on the reference wavefunction.

On the Ground State of Spin Systems with Orbital Degeneracy

In order to understand the properties of the spin system with orbital degeneracy, we first study the ground state of the SU(4) spin-orbital model on a square lattice. The mean-field results suggest that for a small Hund's interaction, the flavor liquid state is stable against the solid state, but with sufficient deviation from the SU(4) limit the long-range order may be attained in 2D system. Furthermore, we employ a variational approach to calculate the phase diagram of the ground state and the temperature-dependent susceptibility by taking into account the Hund's interaction and the anisotropy in orbital wavefunctions. Finally, the implications for the experimental observations on the material, , are discussed.

Spin-orbit Splitting and Lifetime Broadening in the A2△ Electronic State of l-C5H

Optical absorption bands at -18772 and -18807 cm-1, previously assigned to A2A-X2H electronic origin band transitions of the linear carbon-chain radicals CsH and CsD, respectively, have been reinvestigated. The spectra have been recorded in direct absorption applying cavity ring-down spectroscopy to a supersonically expanding acetylene/helium plasma. The improved spectra allow deducing a l-CsH upper state spin-orbit coupling constant X=-0.7（3） cm-1 and a A2A lifetime of 1.65=0.3 ps.

Magnetic-Bottle and Velocity-Map Imaging Photoelectron Spectroscopy of APS-(A=C14H10 or Anthracene):Electron Structure,Spin-Orbit Coupling of APS,and Dipole-Bound State of APS-

Gaseous dibenzo-7-phosphanorbornadiene P-sulfide anions APS （A C14H10 or anthracene） were generated via electrospray ionization, and characterized by magnetic-bottle photoelec- tron spectroscopy, velocity-map imaging （VMI） photoelectron spectroscopy, and quantum chemical calculations. The electron affinity （EA） and spin-orbit （SO） splitting of the APS＂ radical are determined from the photoelectron spectra and Franck-Condon factor simulations to be EA （2.62-4-0.05） eV and SO splitting （43-4-7） meV. VMI photoelectron images show strong and sharp peaks near the detachment threshold with an identical electron kinetic energy （eKE） of 17.9 meV at three different detachment wavelengths, which are therefore assigned to autodetachment from dipole-bound anion states. The B3LYP/6-31＋＋G（d,p） calculations indicate APS has a dipole moment of 3.31 Debye, large enough to support a dipole-bound electron.

Spin-orbit hybrid entanglement quantum key distribution scheme

We propose a novel quantum key distribution scheme by using the SAM-OAM hybrid entangled state as the physical resource.To obtain this state,the polarization entangled photon pairs are created by the spontaneous parametric down conversion process,and then,the q-plate acts as a SAM-to-OAM transverter to transform the polarization entangled pairs into the hybrid entangled pattern,which opens the possibility to exploit the features of the higher-dimensional space of OAM state to encode information.In the manipulation and encoding process,Alice performs the SAM measurement by modulating the polarization stateπ lθx on one photon,whereas Bob modulates the OAM sector state lx' on the other photon to encode his key elements using the designed holograms which is implemented by the computer-controlled SLM.With coincidence measurement,Alice could extract the key information.It is showed that N-based keys can be encoded with each pair of entangled photon,and this scheme is robust against Eve’s individual attack.Also,the MUBs are not used.Alice and Bob do not need the classical communication for the key recovery.

A brief review on Majorana bound states in topological superconductors

Topological superconductivity has drawn much attention recently, and most interests are focused on the Majorana bound states existing at the edges of one-dimensional topological superconductors. These Majorana bound states are ideal platform for studying non-Abelian statistics. Meanwhile, they are proposed to be useful in quantum computation. In this review, we introduce the basic concepts and models in this area. We begin from the Kitaev model, which is the most concise model for one-dimensional topological superconductivity. Then, we discuss how to realize this model with spin-orbit coupling in realistic materials. Finally, we show some simple methods to detect the Majorana bound states and study their novel properties with the help of adjacent quantum dots.

Fulde-Ferrell-Like Molecular States in Spin-Orbit Coupled Ultracold Fermi Gases

We study the molecular state in three-component Fermi gases with a single impurity of ~6Li immersing in a no-interacting Fermi sea of ^(40)K in the presence of an equal weight combination of Rashba-type and Dresselhaustype spin-orbit coupling. In the region where the Fermi sea has two disjointed Fermi surfaces, we find that there are two Fulde–Ferrell-like molecular states with dominating contributions from the lower helicity branch. Decreasing the scattering length or the spin-orbit coupled Fermi energy, we find the Fulde–Ferrell-like molecular state with small center-of-mass momentum is always energy favored and the other one will suddenly disappear.

Effect of Anisotropic Spin-Orbit Coupling on the Ground State of Bose-Einstein Condensate in an External Potential

Spin-orbit coupled Bosonic atoms confined in external potentials open up new avenues for quantumstate manipulation and will contribute to the design and exploration of novel quantum devices.Here we consider a quasi-two-dimensional spin-orbit coupled Bose-Einstein condensate confined in an external harmonic potential,with emphasis on the effects of anisotropic spin-orbit coupling on the equilibrium ground-state structure of such a system.For the cases with spin-orbit coupling solely in x- or y-axis direction,the ground-state structure can develop to the well-known standing wave phase,in which the two components always form an alternative density arrangement.For a two-dimensional anisotropic spin-orbit coupling,the separated lumps first become bend,then form two rows of stripe structure along y direction with further increasing the strength of spin-orbit coupling in x-direction.Furthermore,the distance between these two rows of stripe structure is also investigated in detail.