Reduction of G-orthogonal matrices

The G-orthogonal matrices, defined in this paper, have, unlike orthogonal and Lorentz matrices, complex eigenvalues of modulus not equal to 1, and a corresponding invariant subspace of dimension four. They can be expressed as the exponential of some canonical matrix.     

Nichtlineares invariantes Differential

Zusammenfassung Das invariante Differential eines Vektors ist selbst ein Vektor, der vom Orte xⁱ, von dxⁱ, und von selbst abh?ngig ist. Es wird nun infolge dieser Definition in einigen F?llen die m?gliche Form des invarianten Differentials bestimmt. Enrico Bompiani zu seinem wissenschaftlichen Jubil?um.     

Adsorption and desorption kinetics of Cu and Au on (0001) graphite

The interaction of Au and Cu atoms with the (0001) plane of graphite was studied by mass spectrometric measurements of desorption flux both in the presence and absence of an incident atomic beam. For these systems the condensation coefficient increases from ～0.05 at θ = 0 to unity at θ = 1; furthermore the rate of thermal desorption has a kinetic order of one-half for both systems at low coverage. These observations are consistent with a kinetic model in which two-dimensional nucleation of mobile adsorbed atoms occurs upon adsorption, while the reverse process, loss of atoms from the edges of disc nuclei, is the rate controlling step for desorption. This model implies that bonding of metal atoms to the basal plane of graphite is weak and nonlocalized, with adsorption occurring only when two-dimensional nucleation permits metal-metal bonding.     

A Yukawa interaction in infinite volume

We prove the existence of the Heisenberg picture field operators for quantum fields with a Yukawa interaction. The interaction density $$g:\Psi ^ + (x) \Psi (x) \Phi (x):$$ has a momentum cutoff on the Fermions, but no spatial form factor, and is thus translation invariant.