Double Compton effect with high intensity radiation

Double Compton effect with high intensity radiatio

Do People Make Strategic Moves? Experimental Evidence on Strategic Information Avoidance

The strategic commitment moves that game theory predicts players make may sometimes seem counter-intuitive. We therefore conducted an experiment to see if people make the predicted strategic move. The experiment uses a simple bargaining situation. A player can make a strategic move of committing to not seeing what another player will demand. Our data show that subjects do, but only after substantial time, learn to make the predicted strategic move. We find only weak evidence of physical timing effects.strategic moves; commitment; bargaining; strategic value of information; physical timing effects; endogenous timing; experiment

The lambda-dimension of commutative arithmetic rings

It is shown that every commutative arithmetic ring $R$ has $lambda$-dimension $leq 3$. An example of a commutative Kaplansky ring with $lambda$-dimension 3 is given. If $R$ satisfies an additional condition then $lambda$-dim($R$

Theoretical study of molecular electronic excitations and optical transitions of C60

We report results on ab initio calculations of excited states of the fullerene molecule by using configuration interaction (CI) approach with singly excited determinants (SCI). We have used both the experimental geometry and the one optimized by the density functional method and worked with basis sets at the cc-pVTZ and aug-cc-pVTZ level. Contrary to the early SCI semiempirical calculations, we find that two lowest $^1 T_{1u} \leftarrow {}^1 A_g$ electron optical lines are situated at relatively high energies of ~5.8 eV (214 nm) and ~6.3 eV (197 nm). These two lines originate from two $^1 T_{1u} \leftarrow {}^1 A_g$ transitions: from HOMO to (LUMO+1) ($6h_u \to 3t_{1g}$) and from (HOMO--1) to LUMO ($10h_g \to 7t_{1u}$). The lowest molecular excitation, which is the $1 ^3 T_{2g}$ level, is found at ~2.5 eV. Inclusion of doubly excited determinants (SDCI) leads only to minor corrections to this picture. We discuss possible assignment of absorption bands at energies smaller than 5.8 eV (or $\lambda$ larger than 214 nm).Comment: 6 pages, 1 figure, 9 Table

Nonlinear coupling of continuous variables at the single quantum level

We experimentally investigate nonlinear couplings between vibrational modes of strings of cold ions stored in linear ion traps. The nonlinearity is caused by the ions' Coulomb interaction and gives rise to a Kerr-type interaction Hamiltonian H = n_r*n_s, where n_r,n_s are phonon number operators of two interacting vibrational modes. We precisely measure the resulting oscillation frequency shift and observe a collapse and revival of the contrast in a Ramsey experiment. Implications for ion trap experiments aiming at high-fidelity quantum gate operations are discussed

The crucial importance of the t2gt_{2g}--ege_g hybridization in transition metal oxides

We studied the influence of the trigonal distortion of the regular octahedron along the (111) direction, found in the $\rm CoO_2$ layers. Under such a distortion the $t_{2g}$ orbitals split into one $a_{1g}$ and two degenerated $e_g^\prime$ orbitals. We focused on the relative order of these orbitals. Using quantum chemical calculations of embedded clusters at different levels of theory, we analyzed the influence of the different effects not taken into account in the crystalline field theory; that is metal-ligand hybridization, long-range crystalline field, screening effects and orbital relaxation. We found that none of them are responsible for the relative order of the $t_{2g}$ orbitals. In fact, the trigonal distortion allows a mixing of the $t_{2g}$ and $e_g$ orbitals of the metallic atom. This hybridization is at the origin of the $a_{1g}$--$e_g^\prime$ relative order and of the incorrect prediction of the crystalline field theory

Geometric phase gate on an optical transition for ion trap quantum computation

We propose a geometric phase gate of two ion qubits that are encoded in two levels linked by an optical dipole-forbidden transition. Compared to hyperfine geometric phase gates mediated by electric dipole transitions, the gate has many interesting properties, such as very low spontaneous emission rates, applicability to magnetic field insensitive states, and use of a co-propagating laser beam geometry. We estimate that current technology allows for infidelities of around 10$^{-4}$.Comment: 4 pages, 2 figure