All-solid-state continuous-wave doubly resonant all-intracavity sum-frequency mixer

A new resonator design for doubly resonant continuous-wave intracavity sum-frequency mixing is presented. We generated 212 mW of coherent radiation at 618 nm by mixing the radiation of a 1080-nm Nd(3+):YAlO(3) laser and a 1444-nm Nd(3+):YAG laser. Two different mixing resonator setups and several nonlinear-optical crystals were investigated. So far output is limited by unequal performance of the two fundamental lasers and coating problems of the nonlinear crystals.     

Pulsed laser operation of Y b-dope d KY(WO(4))(2) and KGd(WO(4))(2)

Spectroscopic properties and laser performance of Y b-doped tungstates at pulsed Ti:sapphire laser pumping are reported. Room-temperature lasing near 1025nm is demonstrated in Yb:KY(WO(4))(2) and Yb:KGd(WO(4))(2), with a slope efficiency as great as 86.9%.     

Measurement of muon transfer rate λpt and molecular formation rate λppµ, in solid hydrogen targets,in solid hydrogen targets

The knowledge of muon transfer from protium to tritium is essentially theoretical and the different theoretical values disagree partially. Using solid hydrogen-tritium targets, with different tritium concentrations, we obtained precise experimental results for the transfer rate to tritium and the ppµ molecular formation rate. The time spectra of neutrons and alpha particles produced after dtµ fusion are used to determine the transfer rate _pt and the molecule formation rate _ppµ.     

On the thermodynamicV-representability of one-particle density matrices

We consider thermodynamicallyV-representable one-matrices, i. e., one-particle density matrices that are obtained by reducing the Gibbs grand canonical density matrix of a quantum mechanical many-particle system subject to a suitable external potential, and show them to obey an inequality lower bounding their eigenvalues in terms of those of the one-particle kinetic energy operator. The result imposes a severe constraint on the asymptotic behavior of the eigenvalues of any one-matrix to beV-representable. For noninteracting particles, the corresponding upper bound is also proven, implying that a one-matrix can be interactionlesslyV-representable for at most one temperature. We expect the upper bound to be valid more generally, as is illustrated by a model of coupled harmonic oscillators where theV-representable one-matrices can be explicitly calculated, and discuss its implications for certain aspects of density-matrix functional theory.     

Producing μ−d and μ−t in vacuum

After the feasibility of vacuum isolated ^–d production was demonstrated at TRIUMF in 1989, development was begun on a target system that would take advantage of the process to aid in the understanding of the muon catalyzed fusion cycle. Minimal neutron backgrounds, the ability to use silicon detectors, and compatibility with tritium were considered important for a very versatile target system. The advantages which the target gives in isolating CF process will be outlined.     

Relativistic effects and the constituent quark model of heavy quarkonia

Charmonium \(c\bar c\) and bottomonium \(b\bar b\) are investigated in the framework of a constituent quark model. A scalar confining and a one-gluon exchange (OGE) potential are used in a nonrelativistic reduction to order (p/m)². Therefore the model includes spin dependent as well as spin independent terms. Their influence on the meson mass spectra and decay widths is analysed. We find that the experimental spectra can be reproduced by using a full model as well as by using a reduced version neglecting the spin independent terms. For both versions we calculate leptonic and radiative decay widths including relativistic corrections for the current operators. We find that for leptonic decays inclusion of all terms of the OGE potential gives better results than the non-relativistic formulas. For radiative transitions relativistic corrections are important.