Search

We study the dissociation of Feshbach molecules in ultracold Fermi gases with spin-orbit (SO) coupling. Since SO coupling can induce a quantum transition between Feshbach molecules and the fully polarized Fermi gas, the Feshbach molecules can be dissociated by the SO coupling. We experimentally realize this type of dissociation in ultracold gases of 40K atoms with SO coupling created by Raman beams and observe that the dissociation rate is highly nonmonotonic on both the positive and negative Raman-detuning sides. Our results show that the dissociation of Feshbach molecules can be controlled by different degrees of freedoms, i.e., the SO-coupling intensity or the momenta of theRaman beams, as well as the detuning of the Raman beams. [ABSTRACT FROM AUTHOR]

A generalized Gross-Pitaevskii equation adapted to the U(5) ⊃ SO(5) ⊃ SO(3) symmetry has been derived and solved for the spin-2 condensates. The spin-textile and the degeneracy of the ground state (g.s.) together with the factors affecting the stability of the g.s., such as the gap and the level density in the neighborhood of the g.s., have been studied. Based on a rigorous treatment of the spin-degrees of freedom, the spin-textiles can be understood in an TV-body language. In addition to the ferro, polar, and cyclic phases, the g.s. might in a mixture of them when |M| is not equal to 0 and 2N (M is the total magnetization). The great difference in the stability and degeneracy of the g.s. caused by varying φ (which marks the features of the interaction) and M is notable. Since the root-mean-square radius Rrms is an observable, efforts have been made to derive a set of formulas to relate Rrms and N,ω (frequency of the trap), and φ. These formulas provide a way to check the theories with experimental data. [ABSTRACT FROM AUTHOR]

Based on the spectroscopic constants derived from highly accurate potential-energy surfaces, the SeD radical is identified as a spectroscopic probe for measuring spatial and temporal variation of fundamental physical constants such as the fine-structure constant (denoted as α ***) and the proton-to-electron mass ratio (denoted as μ ***). The ground state of SeD (X²Π), due to spin-orbit coupling, splits into two fine-structure multiplets 2 II 3 and rii . The potential-energy surfaces of these spin-orbit components are derived from a state of the art electronic structure method, MRCI + Q inclusive of scalar relativistic effects with the spin-orbit effects accounted for through the Breit-Pauli operator. The relevant spectroscopic data are evaluated using a Murrel-Sorbie fit to the potential-energy surfaces. The spin-orbit splitting wf between the two multiplets is similar in magnitude with the harmonic frequency we of the diatomic molecule. The amplification factor K derived from this theoretical method for this particular molecule can be as large as 350; on the lower side it can be about 34. The significantly large values of K indicate that the SeD radical can be a plausible experimental candidate for measuring variation in α and μ. [ABSTRACT FROM AUTHOR]

Experimental measurements and calculations of stimulated Raman adiabatic passage transfer efficiencies were made on a sodium gas starting from the 3²S1/2 electronic ground state, passing through the 3²P1/2 and/or the 3²P3/2 to the 5²S1/2 state. The lasers used in the experiments had a pulse width of several picoseconds and were close to the Fourier transform limit. Although the linewidth of the laser was much smaller than the spin orbit splitting between the 3²P2 and 3²P3/2 states, Experiments and calculations reveal that both 3p states play a role in the transfer efficiency when the lasers are tuned to resonance through the 3²P1/2 state, revealing evidence of quantum interference between the competing pathways. [ABSTRACT FROM AUTHOR]

The spin-orbit splitting of graphene π states can be strongly enhanced by external influences such as corrugation or proximity to heavier atoms. Here we investigate experimentally and theoretically whether such strong enhancement is possible for graphene on SiC(0001). By spin- and angle-resolved photoemission we found for two independently grown samples no resolvable spin-orbit splitting with an upper limit of our analysis of 20 meV. Our ab initio calculations predict a low spin-orbit splitting of 0.05 meV with small anisotropy but a local tenfold enhancement where hybridization with SiC substrate bands occurs. [ABSTRACT FROM AUTHOR]